Particle separator filter with an axially extending flow face

ABSTRACT

A two-stage separator system having a housing extending between a first end and a second end. The housing defines a housing inlet, a separator outlet towards the second end, and a filtration outlet on the first end. A filter assembly has a first sheet of filter media coupled to a second sheet of filter media mutually defining a plurality of flutes extending in an axial direction. The filter assembly defines an inlet flow face and an outlet flow face. The filter assembly is disposed in the housing and coupled to the housing about the filtration outlet such that the outlet flow face is in fluid communication with the filtration outlet. The inlet flow face of the filter assembly has an axial flow face length.

The present application claims priority to U.S. Provisional Patent Application No. 62/824,812, filed on Mar. 27, 2019, which is incorporated by reference herein.

TECHNOLOGICAL FIELD

The present disclosure is generally related to a particle separator. More particularly, the present disclosure is related to a particle separator with an axially-extending flow face.

SUMMARY

Some embodiments of the current technology relate to a two-stage separator system. A housing extends between a first end and a second end and defines a housing inlet, a separator outlet towards the second end, and a filtration outlet on the first end. A filter assembly is disposed in the housing. The filter assembly has a first sheet of filter media coupled to a second sheet of filter media mutually defining a plurality of flutes extending in an axial direction, wherein the filter assembly defines an inlet flow face and an outlet flow face. The filter assembly is coupled to the housing about the filtration outlet such that the outlet flow face is in fluid communication with the filtration outlet. The inlet flow face has an axial flow face length.

In some such embodiments, a radial distance is defined between the inlet flow face and the housing, where the radial distance increases for at least a portion of the axial flow face length from the first end towards the second end. Additionally or alternatively, the filter assembly has an outer radial barrier surface extending axially from the filtration outlet beyond the housing inlet. Additionally or alternatively, the filter assembly has an outer radial barrier surface having an axial length from the outlet flow face that is greater than or equal to an axial distance from the filtration outlet to a distal end of the housing inlet.

Additionally or alternatively, the housing inlet defines an airflow pathway that is tangential to an outer radial barrier surface of the filter assembly. Additionally or alternatively, at least a portion of the outer radial barrier surface is defined by the first sheet of filter media. Additionally or alternatively, the inlet flow face defines a taper for at least a portion of the axial flow face length from the first end towards the second end. Additionally or alternatively, the taper increases for at least a portion of the axial flow face length from the first end towards the second end. Additionally or alternatively, the taper continuously changes along the axial flow face length from the first end towards the second end. Additionally or alternatively, the taper continuously increases along the axial flow face length from the first end towards the second end. Additionally or alternatively, the first sheet of filter media is a facing sheet and the second sheet of filter media is a fluted sheet. Additionally or alternatively, the first sheet of filter media and the second sheet of filter media define a coiled configuration about a z-axis extending in the axial direction.

Additionally or alternatively, the system has a rod extending centrally through the filter assembly, the rod having a proximal end positioned towards the outlet flow face and a distal end positioned towards the inlet flow face, and the system has a rod receptacle defined by the second end of the housing, where the rod receptacle is configured to receive a distal end of the rod. Additionally or alternatively, distal end of the rod defines a handle. Additionally or alternatively, the filter assembly has a circular cross-section. Additionally or alternatively, the filter assembly has a plurality of first sheets of filter media and a plurality of second sheets of filter media in an alternating, stacked configuration and a radial sleeve disposed about the stacked first sheets of filter media and second sheets of filter media. Additionally or alternatively, the housing inlet is defined towards the first end of the housing.

The above summary is not intended to describe each embodiment or every implementation. Rather, a more complete understanding of illustrative embodiments will become apparent and appreciated by reference to the following Detailed Description of Exemplary Embodiments and claims in view of the accompanying figures of the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present technology may be more completely understood and appreciated in consideration of the following detailed description of various embodiments in connection with the accompanying drawings.

FIG. 1 is a side view of an example two-stage separator system consistent with the present disclosure.

FIG. 2 is a cross-sectional view of a housing of an example separator system consistent with FIG. 1.

FIG. 3 is a perspective view of an example filter assembly consistent with the technology disclosed herein.

FIG. 4A is a perspective view of another example filter assembly consistent with the technology disclosed herein.

FIG. 4B is a detail view A′ of FIG. 4A.

FIG. 5 is a side cut-away view of another example filter assembly consistent with the technology disclosed herein.

FIG. 6A is example filter media consistent with some embodiments.

FIG. 6B is another example filter media consistent with some embodiments.

FIG. 6C is yet another example filter media consistent with some embodiments.

FIG. 6D is an example filter media consistent with some embodiments.

FIG. 7 is a perspective view of another example filter assembly consistent with the technology disclosed herein.

FIG. 8 depicts a cross-sectional view of an example filter assembly consistent with the technology disclosed herein.

FIG. 9A is a perspective view of another example filter assembly consistent with the technology disclosed herein.

FIG. 9B is a facing view of a first face of the filter assembly of FIG. 6 a.

FIG. 10 is a perspective view of yet another example filter assembly consistent with the technology disclosed herein.

FIG. 11 is a perspective view of yet another example filter assembly consistent with the technology disclosed herein.

FIG. 12 is a perspective view of yet another example filter assembly consistent with the technology disclosed herein.

FIG. 13 is a perspective view of yet another example filter assembly consistent with the technology disclosed herein.

FIG. 14A is a side view of another example filter assembly consistent with the technology disclosed herein.

FIG. 14B is a facing view of filter media consistent with FIG. 14A.

FIG. 15A is a cross-sectional view of another example filter assembly consistent with the technology disclosed herein.

FIG. 15B is a facing view of filter media consistent with FIG. 15A.

FIG. 16A is a cross-sectional view of another example filter assembly consistent with the technology disclosed herein.

FIG. 16B is a facing view of filter media consistent with FIG. 16A.

FIG. 17A is a perspective view of another example filter assembly consistent with the technology disclosed herein.

FIG. 17B is a facing view of filter media consistent with FIG. 17A.

FIG. 18 is a side cut-away of a filter assembly consistent with the technology disclosed herein.

FIG. 19 is another side cut-away view of a filter assembly consistent with the technology disclosed herein.

FIG. 20 is another side cut-away view of a filter assembly consistent with the technology disclosed herein.

FIG. 21 is a cross-sectional view of filter media consistent with various embodiments.

FIG. 22 is a facing schematic view of a flow face of an example filter assembly consistent with the technology disclosed herein.

FIG. 23 is a cross-sectional schematic view of a filter assembly consistent with the technology disclosed herein.

FIG. 24 is a cross-sectional view of another example two-stage separator system consistent with some embodiments.

FIG. 25a depicts a schematic of a first example cross-section associated with FIG. 2.

FIG. 25b depicts a schematic of a second example cross-section associated with FIG. 14 a.

FIG. 26a depicts a schematic of a first example cross-section associated with a system incorporating a filter assembly similar to that depicted in FIG. 14 a.

FIG. 26b depicts a schematic of a second example cross-section associated with a system incorporating a filter assembly similar to that depicted in FIG. 14 a.

FIG. 27a depicts a schematic of a first example cross-section associated with another example system consistent with some embodiments.

FIG. 27b depicts a schematic of a second example cross-section associated with the example system of FIG. 27 a.

FIG. 28 is a cross-sectional view of yet another example two-stage separator system consistent with some embodiments.

FIG. 29 is a cross-sectional view of an example standard two-stage separator system consistent with the previous technologies.

The figures are rendered primarily for clarity and, as a result, are not necessarily drawn to scale. Moreover, various structure/components, including but not limited to fasteners, electrical components (wiring, cables, etc.), and the like, may be shown diagrammatically or removed from some or all of the views to better illustrate aspects of the depicted embodiments, or where inclusion of such structure/components is not necessary to an understanding of the various exemplary embodiments described herein. The lack of illustration/description of such structure/components in a particular figure is, however, not to be interpreted as limiting the scope of the various embodiments in any way.

DETAILED DESCRIPTION

FIG. 1 is a side view of an example two-stage separator system 1900 consistent with the present disclosure. The separator system 1900 has a housing 1910 that houses a filter assembly 1950 disposed therein. The filter assembly 1950 can be generally consistent with filter assemblies described herein consistently with FIGS. 3-24.

The housing 1910 generally extends between a first end 1912 and a second end 1914. The housing 1910 defines an interior volume 1916. In various embodiments the housing 1910 extends in an axial direction defined by a central axis z. The housing 1910 defines a housing inlet 1920, a separator outlet 1930 towards the second end 1914, and a filtration outlet 1940 on the first end 1912. A filter assembly 1950 is positioned in the interior volume 1916. The housing 1910 is configured to receive unfiltered fluid, such as air, through the housing inlet 1920, allow expulsion of separated particulates through the separator outlet 1930, and allow filtered air to exit through filtration outlet 1940. This functionality will be described in more detail below.

In various embodiments, the housing 1910 has a main portion 1960 and an access cover 1970 that are detachably coupled. The main portion 1960 can define the first end 1912 of the housing 1910 and the access cover 1970 can define the second end 1914 of the housing 1910. The main portion 1960 and the access cover 1970 are detachably coupled for removal and installation of a filter assembly 1950 through a second end 1962 of the main portion 1960. The access cover 1970 encloses the second end 1962 of the main portion 1960 of the housing 1910.

The main portion 1960 and the access cover 1970 are detachably coupled with mutually defined mating features 1980. In the current example, the access cover 1970 defines a latch 1982 and the second end 1962 of the main portion 1960 defines a latch receptacle 1984, although other configurations are certainly contemplated. For example, the main portion 1960 and the access cover 1970 can define a mating threaded connection, a bayonet connection, and the like.

The housing inlet 1920 can be defined by a tubular structure 1922 (that is not necessarily circular in cross-section) that extends outwardly from the housing 1910. The housing inlet 1920 is defined by the main portion 1960 of the housing 1910. In various embodiments, including that depicted, the housing inlet 1920 is a tangential inlet, meaning that airflow through the housing inlet 1920 is directed in a tangential direction relative to the filter assembly 1950. In other words, in some embodiments the housing inlet is generally not directed toward the central axis z of housing 1910. Housing inlets 1920 having alternate configurations can also be used, however. In some embodiments, such as that depicted, the housing inlet 1920 is defined towards the first end 1912 of the housing 1910.

In the present example, the housing inlet 1920 is in fluid communication with an interior flow guide 1924, which is configured to receive fluid flowing into the housing 1910 from the housing inlet 1920 and direct the fluid in a spiraled flow path about the interior volume 1916 of the housing 1910. The flow guide 1924 can be a ramp, deflector, wall, channel, or other structure extending from the housing inlet 1920 that defines a portion of a spiral flow path in the interior volume 1916 of the housing 1910. Some embodiments may lack a flow guide 1924. In some other embodiments a flow guide can be defined by the filter assembly 1950, which will be described in more detail, below.

The separator outlet 1930 is generally defined by an ejector tube 1932 that extends outwardly from the housing 1910. The ejector tube 1932 is defined by the access cover 1970 of the housing 1910. The ejector tube 1932 allows for expulsion of at least a portion of the particulate contaminants from the unfiltered fluid during operation. In some embodiments, the ejector tube 1932 has an evacuator valve arrangement 1934 to selectively evacuate the collected particulate contaminants.

The filtration outlet 1940 is defined by an outlet tube 1942 that extends outwardly from the housing 1910. The filtration outlet 1940 is defined by the main portion 1960 of the housing 1910. In the current example, the filtration outlet 1940 extends axially away from the housing on the first end of the housing 1910.

In an example implementation consistent with FIG. 1, air enters the system 1900 through the housing inlet 1920, in a tangential direction to the filter assembly 1950. The housing inlet 1920 directs the airflow to the interior flow guide 1924, which guides the airflow along a spiraled path about the filter assembly 1950 towards the second end 1914 of the housing 1910. Such airflow can result in separation of at least a portion of the relatively larger particles in the air, which can have sufficient momentum to travel to the second end 1914 of the housing 1910. The particles can migrate to ejector tube 1932 and be ejected through the separator outlet 1930 via the evacuator valve arrangement 1934.

The remainder of the particulate in the air that is not ejected through the separator outlet 1930 is directed through the filter assembly 1950 by a vacuum force. The air is filtered by the filter assembly 1950 and exits the housing 1910 through the filtration outlet 1940 of the outlet tube 1942 on the first end 1912 of the housing 1910. The filtered air can then be directed to the relevant external system.

FIG. 2 is a first example cross-sectional view consistent with the separator system 1900 of FIG. 1. The system 1900 can have the same components, structure, and possible modifications as described above. In general, the housing 1910 extends between a first end 1912 and a second end 1914 and defines a housing inlet 1920 towards the first end 1912. The housing 1910 defines a separator outlet 1930 towards the second end 1914 and a filtration outlet 1940 on the first end 1912.

A filter assembly 1950 is disposed in the housing 1910, that is generally configured to filter air within the housing 1910. The filter assembly 1950 has an inlet flow face 1952, an outlet flow face 1954, and filter media 1956 extending in the axial direction z. The filter media 1956 extends between the inlet flow face 1952 and the outlet flow face 1954. A “flow face” as defined herein is the side of the filter assembly through which fluid is configured to enter or exit the filter assembly.

The inlet flow face 1952 is configured to receive unfiltered air from within the housing 1910. The outlet flow face 1954 is configured to release air that has been filtered by the filter media 1956. The inlet flow face 1952 and the outlet flow face 1954 are defined on opposite axial ends of the filter assembly 1950. In various embodiments filter assembly 1950 is configured such that fluid is limited to entering the filter assembly 1950 in the axial direction. In various embodiments filter assembly 1950 is configured such that fluid is limited to exiting the filter assembly 1950 in the axial direction. In some embodiments the outlet flow face is planar, but in other embodiments the outlet flow face is non-planar, which will be described below with respect to FIGS. 3-20.

The filter assembly 1950 is coupled to the housing 1910 about the filtration outlet 1940 such that the outlet flow face 1954 is in fluid communication with the filtration outlet 1940. In various embodiments, the filter media 1956 surrounding the outlet flow face 1954 is coupled to the housing 1910 about the filtration outlet 1940. In the current example, the filter assembly 1950 has a potting feature 1953 that is a radial potting sleeve configured to receive a first end of the filter media 1956 about the outlet flow face 1954. The first end of the filter media 1956 can be coupled to the potting feature 1953 using adhesives, gaskets, compression fits, and/or through additional or alternative structures. The potting feature 1953 and the first end of the filter media 1956 are configured to form a seal about the outlet flow face 1954. In various embodiments, the potting feature can be sealed with an adhesive to the first end of the filter media 1956.

The potting feature 1953 is generally configured to form a sealed connection between the outlet flow face 1954 of the filter media 1956 and the filtration outlet 1940 of the housing 1910. In particular the potting feature 1953 and the housing 1910 are configured to form a sealed connection to isolate the outlet flow face 1954 and the filtration outlet 1940 from the remainder of the interior volume 1916 of the housing 1910. The potting feature 1953 can be substantially impermeable to airflow therethrough. The potting feature 1953 can be impermeable to airflow therethrough.

In this example, the housing 1910 has a filter receptacle 1926 that is configured to receive the potting feature 1953 and the first end 1951 of the filter media. In some embodiments a radial seal can be disposed radially between an outer radial surface 1955 of the potting feature 1953 and an inner radial surface 1927 of the housing 1910 within the filter receptacle 1926. In some embodiments an annular axial seal can be disposed between an annular surface 1957 defined by the potting feature 1953 and a mating surface of the housing 1910 within the filter receptacle 1926. In some alternate examples, the potting feature and the filter receptacle of the housing can define a mating structure that accommodates a radial seal between an inner radial surface of the potting feature and an outer radial surface of the housing within the filter receptacle.

The filter assembly 1950 has an outer radial barrier surface 1958 between the inlet flow face 1952 and the outlet flow face 1954. In some embodiments, the outer radial barrier surface 1958 can be configured to guide airflow tangentially about the filter assembly 1950. In some such embodiments, the housing inlet 1920 defines an airflow pathway that is tangential to an outer radial barrier surface 1958 of the filter assembly 1950.

The outer radial barrier surface 1958 is generally configured to obstruct airflow into the filter assembly 1950 through the outer radial barrier surface 1958. In some embodiments, at least a portion of the outer radial barrier surface 1958 is defined by filter media 1956 that is a sheet of filter media. In some embodiments, the outer radial barrier surface 1958 is defined by a separate sleeve disposed about the filter media 1956. The sleeve can be constructed of a material having a higher resistance to airflow therethrough compared to the inlet flow face 1952 of the filter assembly 1950, which can discourage airflow through the sleeve and, therefore, encourage spiraling airflow about the filter assembly towards the second end 1914 of the housing 1910. Such a configuration can increase the efficiency of the separator. In some embodiments the sleeve is constructed of a cellulose material, in some embodiments the sleeve is constructed of a polymeric material.

The outer radial barrier surface 1958 has a length L_(surface) extending in the axial direction. The outer radial barrier surface 1958 can extend from the outlet flow face 1954 towards the inlet flow face 1952. In examples, the outer radial barrier surface 1958 is partially defined by the potting feature 1953. As such, the length L_(surface) of the outer radial barrier surface 1958 extends axially from the potting feature 1953 to the inlet flow face 1952. In some embodiments, the length L_(surface) of the outer radial barrier surface 1958 is greater than or equal to an axial distance D from the filtration outlet 1940 to a distal end of the housing inlet 1920. The “distal end of the housing inlet” is the furthest portion of the housing inlet 1920 from the filtration outlet 1940 in the axial direction. In some embodiments, the outer radial barrier surface 1958 extends axially from the filtration outlet 1940 beyond the housing inlet 1920. Such a configuration encourages spiraling airflow about the filter assembly 1950 towards the second end 1914 of the housing 1910.

In some embodiments, the outer radial barrier surface 1958 can define a flow guide that is configured to receive fluid flowing into the housing 1910 from the housing inlet 1920 and direct the fluid in a spiraled flow path about the interior volume 1916 of the housing 1910. The flow guide can be a ramp, deflector, wall, channel, or other structure extending at least partially around the outer radial barrier surface 1958.

The inlet flow face 1952 of the filter assembly 1950 has a flow face length L_(inlet) in the axial direction z. In some embodiments, the inlet flow face 1952 defines a taper for at least a portion of the axial flow face length L_(inlet) from the first end 1912 towards the second end 1914 of the housing 1910. Such a taper can help encourage spiraling airflow about the filter assembly 1950 towards the second end 1914 of the housing 1910 and discourage settling of contaminants across the inlet flow face 1952. In some embodiments where the inlet flow face 1952 defines a taper for at least a portion of the axial flow face length L_(inlet), the taper increases for at least a portion of the axial flow face length L_(inlet) from the first end 1912 towards the second end 1914, such as in the example shown in FIG. 2, where the general shape defined by the inlet flow face 1952 is a rounded cone. The taper of the inlet flow face 1952 can continuously change along the axial flow face length L_(inlet) from the first end 1912 towards the second end 1914. Indeed, in the current example, the taper of the inlet flow face 1952 continuously increases along the axial flow face length L_(inlet) from the first end 1912 towards the second end 1914.

A radial distance R_(1,2) is generally defined between the inlet flow face 1952 and the housing 1910 relative to the central axis z. In various embodiments, the radial distance R_(1,2) increases for at least a portion of the axial flow face length L_(inlet) from the first end 1912 towards the second end 1914 of the housing 1910. as demonstrated by a first radial distance R₁ and a second radial distance R₂. The first radial distance R₁ is measured from a point on the inlet flow face 1952 that is in axial alignment with the point on the inlet flow face 1952 from which the second radial distance R₂ is measured, for purposes of this comparison. As such, the first radial distance R₁ and a second radial distance R₂ are in parallel and in axial alignment. Increasing the radial distance R_(1,2) along the axial flow face length L_(inlet) can help encourage spiraling airflow about the filter assembly 1950 towards the second end 1914 of the housing 1910. Other configurations, however, are certainly contemplated.

In the current example, the housing 1910 maintains a relatively consistent distance from the central axis z. In some embodiments, however, the housing 1910 can define a taper. In such embodiments, the housing 1910, and particularly the interior volume 1916 of the housing 1910, can taper for at least a portion of the axial length from the first end 1912 to the second end 1914 or from the second end 1914 to the first end 1912. However, the radial distance between the inlet flow face 1952 and the housing 1910 can increase along at least a portion of the axial length of the inlet flow face 1952 from the first end 1912 to the second end 1914 of the housing 1910.

The annulus defined between the inlet flow face 1952 and the housing 1910 in a cross-section perpendicular to the z-axis has an increasing area along at least a portion of the axial length of the inlet flow face 1952 from the first end 1912 to the second end 1914 of the housing 1910. FIGS. 25a and 25b depict simplified schematics of such example cross-sections, where FIG. 25a is a cross-section at R₁ in FIG. 2, and FIG. 25b is a cross-section at R₂ in FIG. 2. While FIGS. 25a and 25b depict the cross-sectional shape of the inlet flow face 1952 as having a smooth circular shape for simplicity, in various embodiments flute profiles will form the outer perimeter of the inlet flow face 1952. For example, a series of peaks and valleys that define the flute profiles in the media are arranged about the central axis z to define a generally circular shape.

The area of the annulus A₁ defined between the outer circumferential limit of the inlet flow face 1952 and the housing 1910 in FIG. 25a is less than the area of the annulus A₂, where A₁ is at a first position P₁ along the axial length of the inlet flow face 1952 and A₂ is at a second position P₂ along the axial length of the inlet flow face 1952. “Annulus” is defined herein as a shape defined between an inner boundary and an outer boundary, such as a ring, where the inner boundary and the outer boundary are not necessarily circles, are not necessarily concentric, and are not necessarily the same shape. FIGS. 25a and 25b also depict the radial distances R_(1,2) defined between the inlet flow face 1952 and the housing 1910 relative to the central axis z at the first position P₁ and the second position P₂ along the axial length of the inlet flow face 1952. The second radial distance R₂ is greater than the first radial distance R₁.

As mentioned above, in the current example, the general shape defined by the inlet flow face 1952 forms a rounded, regular cone. By “regular” it is meant that the cone is generally symmetric about the z-axis. The cone is not necessarily perfectly symmetric about the z-axis. In some other embodiments, the inlet flow face can have alternate configurations, some of which are described below with reference to other figures described herein. For example, the general shape defined by the inlet flow face can be irregular, in other words asymmetric about the z-axis. FIGS. 14A, 26 a and 26 b discussed in detail below, provides one such example where a flow face forms the general shape of a rounded, oblique cone.

In various embodiments, the filter assembly 1950 is positioned centrally in the housing 1910 such that the z-axis extends centrally through the filter assembly 1950. In the example currently depicted, the filter media 1956 is at least a first sheet of filter media and a second sheet of filter media in a coiled configuration about the z-axis, which will be described in more detail with respect to FIG. 3, below. In some other embodiments, the filter assembly is eccentric in the housing such that the z-axis does not extend centrally through the filter assembly. FIGS. 27a and 27b depict cross sections perpendicular to the central axis z associated with an example where a filter assembly 1950′ is positioned eccentrically in the housing 1910. The example filter assembly 1950′ can otherwise be consistent with the filter assembly of FIG. 2, except that the filter assembly 1950′ has a central axis Z extending axially through the filter assembly 1950′ distinct from the central axis z of the housing 1910.

Similar to FIGS. 25a and 25b discussed above, the area of the annulus A₁ defined between inlet flow face 1952′ and the housing 1910 in FIG. 27a is less than the area of the annulus A₂. A₁ is at a first position P₁ along the axial length of the inlet flow face 1952′ and A₂ is at a second position P₂ along the axial length of the inlet flow face 1952′. Furthermore, the radial distances R_(1,2) defined between the inlet flow face 1952′ and the housing 1910 relative to the central axis z at the first position P₁ and the second position P₂ along the axial length of the inlet flow face 1952′ are different. The second radial distance R₂ is greater than the first radial distance R₁, where the first radial distance R₁ and the second radial distance R₂ are in axial alignment and in parallel.

Returning to the example of FIGS. 1-2, the filter assembly 1950 has a rod 1990 that the filter media 1956 is coiled about. As such, the rod 1990 extends centrally through at least a portion of the filter assembly 1950. In some embodiments the rod 1990 extends entirely through the filter assembly 1950. The rod 1990 is a single component, or can be constructed of multiple components that are coupled or uncoupled to each other. In some embodiments the rod 1990 does not extend entirely through the filter assembly 1950, while in other embodiments, the rod 1990 does extend entirely through the filter assembly 1950. In one example the rod 1990 has a tubular extension with plugs disposed in each end of the tubular extension. In such an embodiment a plug can form a handle, which is described in more detail below.

A rod receptacle 1992 defined by the second end 1914 of the housing 1910 is configured to receive a distal end 1994 of the rod 1990. The rod 1990 can have a proximal end positioned towards the outlet flow face 1954 (not currently visible). In some embodiments a proximal end of the rod 1990 is positioned between the inlet flow face 1952 and the outlet flow face 1954. The distal end of the rod 1990 is positioned towards the inlet flow face 1952. In such an embodiment the rod receptacle 1992 is a positioning feature that helps maintain positioning of the inlet flow face 1952 of the filter assembly 1950 relative to the second end 1914 of the housing 1910. Particularly here, the rod receptacle 1992 is a centering feature that helps maintain centering of the inlet flow face 1952 filter assembly 1950 relative to the second end 1914 of the housing 1910. In some embodiments, the distal end 1994 of the rod 1990 defines a handle that can be manually grasped by a user which can aid in removal and installation of the filter assembly 1950 relative to the housing 1910.

In various embodiments, a rod can be omitted from the system. In some other embodiments, rather than defining a rod receptacle as depicted in FIG. 2, the second end of the housing can define a rod structure extending axially towards the first end of the housing. The inlet flow face of the filter assembly can be configured to receive the rod structure for positioning the inlet flow face of the filter assembly relative to the second end of the housing. For example, a rod receptacle can be coupled to the inlet flow face of the filter assembly. In some such embodiments the rod receptacle can define a handle structure that can be grasped by a user, such as one or more radial projections extending from the rod receptacle. Other features can also be implemented to secure the position of the inlet flow face of the filter assembly relative to the second end of the housing.

In some embodiments, the housing 1910 can have a positioning feature that directly receives the distal end of the inlet flow face 1952. For example, the second end 1914 of the housing 1910 can define an annular protrusion extending circumferentially about the central axis of the filter assembly 1950. The annular protrusion can be configured to surround the distal end of the inlet flow face 1952. In some embodiments, the annular protrusion can be configured to frictionally engages the distal end of the inlet flow face 1952. In various embodiments an annular protrusion as a positioning feature is omitted from the separator system 1900.

FIG. 3 depicts an example filter assembly consistent with the systems depicted in FIGS. 1-2. The filter assembly 1 is constructed of filter media 10 defining a first flow face 20, a second flow face 30, and a plurality of flutes 40 extending from the first flow face 20 to the second flow face 30 in an axial direction. In the current example, the first flow face is defined on a first end 12 of the filter assembly 1 and the second flow face 30 is defined on a second, opposite end 14 of the filter assembly 1. The first end 12 and the second end 14 are opposite axial ends of the filter assembly 1. Consistent with FIG. 2, above, the first flow face 20 can be the inlet flow face and the second flow face 30 can be the outlet flow face. The first flow face 20 defines an axial flow face length L, as described above. The first flow face 20 defines a taper for at least a portion of the axial flow face length, as described above.

The filter media 10 is a plurality of sheets of filter media, specifically a first sheet of filter media 50 and a second sheet of filter media 60. The second sheet of filter media 60 is adjacent to the first sheet of filter media 50. The first sheet of filter media 50 and the second sheet of filter media 60 mutually define the plurality of flutes 40. The filter media 10 defines a coiled configuration about a Z-axis. Accordingly, each of the first sheet of filter media 50 and the second sheet of filter media 60 defines a coiled configuration around the Z-axis. As such, the plurality of flutes 40 are also in a coiled configuration about the Z-axis.

The first sheet of filter media 50 and the second sheet of filter media 60 are generally elongate, which enables the first sheet of filter media 50 and the second sheet of filter media 60 to be coiled about the Z-axis, which extends in the axial direction, to form a filter assembly. In this example, the first sheet of filter media 50 and the second sheet of filter media 60 are continuous, meaning that the first sheet of filter media 50 and the second sheet of filter media 60 are portions of a single cohesive sheet of filter media. The first sheet of filter media 50 and the second sheet of filter media 60 are separated by a fold 70. The fold 70 defines the second flow face 30 of the filter assembly. The first sheet of filter media 50 defines a first edge 52 and the second sheet of filter media 60 defines a second edge 62. The first edge 52 and the second edge 62 mutually define the first flow face 20 of the filter assembly 1. An “edge” of a media sheet is defined herein as the outer limit of the media sheet and is distinguished from the fold 70.

In some alternate embodiments, which will be described in more detail below, the first sheet of filter media 50 and the second sheet of filter media 60 are separate sheets, in which case, the second flow face would be defined by the edges of each of the sheets of filter media. Further, in various embodiments, the first sheet of filter media can be non-fluted and characterized as a facing sheet of filter media abutting the fluted second sheet of filter media to form single facer media.

In examples consistent with the current embodiment, both the first sheet of filter media 50 and the second sheet of filter media 60 are each fluted. The term “fluted” as used herein is synonymous with the term “corrugated,” which refers to a series of alternating elongate ridges/peaks, and elongate grooves/valleys. The term “flutes” is used herein to refer to the elongate channels mutually defined by adjacent portions of media. In the current embodiment the plurality of flutes are parallel, but in some other embodiments the plurality of flutes are not parallel.

The filter assembly 1 is generally constructed to define a fluid pathway 16 between the first flow face 20 and the second flow face 30 through the filter media 10 such that the fluid is filtered by the filter media 10. In particular, the plurality of flutes 40 defines the fluid pathway 16 either (1) into the filter assembly 1 then to the filter media 10 (“inlet flutes”), or (2) from the filter media 10 out of the filter assembly 1 (“outlet flutes”). While each of the figures provided in the present application depict fluid pathways in a particular direction through the depicted filter assemblies for clarity, it will be understood that the fluid pathways can also be in the reverse direction in various examples.

Each of the plurality of flutes 40 defines a flute opening 42 and a flute closure 70. The flute opening 42 forms an end-most portion of the fluid pathway 16 along the flute, to accommodate fluid flow into or out of the filter assembly 1. The flute closure 70 obstructs fluid flow along the flute, thereby defining a portion of the fluid pathway 16 through the filter media 10. In the current example, a plurality of inlet flutes defines the flute opening 42 at the first flow face 20. A flute closure 70 can be defined towards the second flow face 30 in some embodiments. In some embodiments, including the one depicted, the flute closure 70 is adjacent to the second flow face 30. More particularly, the flute closure 70 can abut the second flow face 30. The flute closure 70 can have a variety of different configurations, but in the current embodiment, the flute closure 70 is defined by the fold 70, which defines the second flow face 30. In some other embodiments, flute closures can be defined between the first flow face 20 and the second flow face.

In the current embodiment, the volume defined between an outer surface 56 of the first sheet of filter media and the outer surface 66 of the second sheet of filter media defines an outlet pathway of the fluid pathway 16 that is not necessarily characterized as being defined by a plurality of flutes. The phrase “outer surface” is defined as the surfaces of the first sheet of filter media and the second sheet of filter media that are facing away from each other if the filter media 10 were arranged as a flat sheet (when uncoiled. The outlet pathway extends from an obstruction 72 to an opening defined at the second end 14 of the filter assembly 1 between the coiled fold 70.

The obstruction 72 can be disposed within the coil and outside of the plurality of flutes 40 such that fluids passing through the first flow face 20 and second flow face 30 of the filter assembly 1 must first pass through the filter media 10. Additional obstructions can also be disposed in any other gaps in the filter media to prevent fluid flow there-through, such as around the outer perimeter of the filter assembly 1 and in a central opening of the filter assembly 1. An obstruction can be formed through depositing an adhesive, such as a glue bead at the relevant location.

Each of the plurality of flutes 40 defines a flute distance between the first flow face 20 and the second flow face 30. The “flute distance” as defined herein is the distance between a first end of a particular flute at the first flow face of the filter assembly and the second end of the particular flute at the second flow face of the filter assembly. In the current embodiment each of the plurality of flutes 40 are straight and, as such, the length of the flute is equal to the “flute distance” as defined herein. However, in some alternative embodiments, the “flute distance” is unequal to the length of the flute, such as in embodiments where the flutes are curved or otherwise do not form a single straight line. Furthermore, the “flute distance” is defined to be the maximum distance between the ends of the flute, in embodiments where the ends of the flute are not a consistent distance apart.

In the current embodiment, a first flute 44 of the plurality of flutes 40 defines a first flute distance D₁ between the first flow face 20 and the second flow face 30 and a second flute 46 of the plurality of flutes 40 defines a second flute distance D₂ between the first flow face 20 and the second flow face 30. In some examples, the first flute distance D₁ is less than the second flute distance D₂, as currently depicted. In some other examples, the first flute distance D₁ is greater than the second flute distance D₂. In certain embodiments, the first flute distance D₁ and the second flute distance D₂ differ by greater than 2 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by at least 5 mm, at least 8 mm or even at least 15 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by 3 mm to 20 mm, 10 mm to 20 mm, or 15 mm to 25 mm.

In some embodiments, a third flute 48 of the plurality of flutes 40 defines a third flute distance D₃ between the first flow face 20 and the second flow face 30. The third flute distance D₃ will generally differ from at least one of the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. In some embodiments the third flute distance D₃ differs from both the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. The third flute distance D₃ can differ from one or both the first flute distance D₁ and the second flute distance D₂ by similar ranges described above. In the current example, the third flute distance D₃ is greater than the first flute distance D₁ and the second flute distance D₂. In some other examples, the third flute distance D₃ is greater than one of the first flute distance D₁ and the second flute distance D₂, and less than the other of the first flute distance D₁ and the second flute distance D₂, as will be appreciated.

The differences in flute distances between the first flow face 20 of the filter assembly 1 and the second flow face 30 of the filter assembly 1 is also evidenced by the shapes of the flow faces relative to each other. In various embodiments, at least one of the first flow face 20 and the second flow face 30 is non-planar. In various embodiments, at least one of the first flow face 20 and the second flow face 30 is substantially planar. A “planar” flow face as defined herein means that the surface(s) of the media defining the flow face form an imaginary plane within a 2 mm margin of error.

In some examples consistent with this particular embodiment, the first flow face 20 is non-planar and the second flow face 30 is planar. In some other examples consistent with this particular embodiment, the first flow face 20 is non-planar and the second flow face 30 non-planar. Here the first flow face 20 defines a spiral about the Z-axis that extends in the axial direction. While the second flow face 30 is obstructed from view in the current illustration, it will be appreciated that the second flow face 30 can be non-planar or planar. For example, in some embodiments the second flow face 30 can be recessed and extend inward relative to the filter assembly, similar to the flow faces depicted in FIG. 18.

It will be appreciated that, in some alternative embodiments, the first flow face 20 can be planar and the second flow face 30 can be non-planar. In some embodiments at least one flute in the plurality of flutes 40 defines a flute opening that is non-planar, where “non-planar” means that the flute opening does not define a plane within a 2 mm margin of error.

In examples consistent with the current embodiment, the obstruction 72 is disposed adjacent to the second edge 62 of the second sheet of filter media 60 along the length of the second sheet of filter media 60. As the second edge 62 of the second sheet of filter media 60 is non-planar, the obstruction 72 also is non-planar. In some embodiments where a filter face is non-planar, an obstruction disposed adjacent to the filter face is also non-planar. However, in other embodiments, where a filter face is non-planar, an obstruction disposed adjacent to that filter face is planar, such as in the embodiment depicted in FIG. 4A.

FIG. 4A depicts another example filter assembly 100 consistent with the technology disclosed herein. The filter assembly 100 is constructed of filter media 110 defining a first flow face 120, a second flow face 130, and a plurality of flutes 140 extending from the first flow face 120 to the second flow face 130. In the current example, the first flow face 120 is defined on a first end 102 of the filter assembly 100 and the second flow face 130 is defined on a second, opposite end 104 of the filter assembly 100. The first flow face 120 defines a first axial flow face length L₁ and the second flow face 130 defines a second axial flow face length L₂. In the current example, the first flow face 120 does not define a taper.

The filter media 110 is a plurality of sheets of filter media, specifically a first sheet of filter media 150 and a second sheet of filter media 160. The second sheet of filter media 160 is adjacent to the first sheet of filter media 150. The first sheet of filter media 150 and the second sheet of filter media 160 mutually define the plurality of flutes 140. The filter media 110 defines a coiled configuration about a Z-axis. Accordingly, each of the first sheet of filter media 150 and the second sheet of filter media 160 defines a coiled configuration about the Z-axis. As such, the plurality of flutes 140 are also in a coiled configuration about the Z-axis. To depict components not otherwise visible, an end portion 101 of the filter media 110 is depicted in a cut-away view that extends outward from the coil, but generally the substantial length of the filter media 110 is in a coiled configuration. In this example, the plurality of flutes 140 are generally parallel.

The first sheet of filter media 150 and the second sheet of filter media 160 are generally elongate. In this example, the first sheet of filter media 150 and the second sheet of filter media 160 are discontinuous, meaning that the first sheet of filter media 150 and the second sheet of filter media 160 are separate sheets of filter media. In examples consistent with the current embodiment, the first sheet of filter media 150 is a fluted sheet and the second sheet of filter media 160 is a facing sheet, where a “facing sheet” is generally defined as a planar, unfluted sheet.

The first sheet of filter media 150 defines a first edge 152 and a second edge 154 that is opposite the first edge 152. The first edge 152 defines the first flow face 120 and the second edge 154 defines the second flow face 130. The first sheet of filter media 150 has a first width W₁ that is defined by the perpendicular distance from first edge 152—or first flow face 120—to the second edge 154—or second flow face 130, where the first width W₁ is substantially constant along the length of the first sheet of filter media 150. Similarly, the second sheet of filter media 160 defines a third edge 162 and a fourth edge 164 that is opposite the third edge 162. The third edge 162 defines the first flow face 120 and the fourth edge 164 defines the second flow face 130. The second sheet of filter media 160 has a second width W₂ that is defined by the perpendicular distance from the third edge 162—or the first flow face 120—to the fourth edge 164—or the second flow face 130, where the width is substantially constant along the length of the second sheet of filter media 160. In the current embodiment, the first width W₁ differs from the second width W₂ by greater than 2 mm.

The filter assembly 100 is generally constructed to define a fluid pathway 116 between the first flow face 120 and the second flow face 130 through the filter media 110 such that the fluid is filtered by the filter media 110. Each of the plurality of flutes 140 defines a flute opening 142, which is more clearly visible in FIG. 4b as a detail view of FIG. 4a . Each of the plurality of flutes 140 defines a flute closure 170, which is visible in FIG. 4a because a portion of the first sheet of filter media 150 is cut away for clarity. In the current example, the flute opening 142 is defined at the first flow face 120 and the flute closure 170 is defined towards the second flow face 130. In some embodiments, including the one depicted, the flute closure 170 is adjacent to the second flow face 130. More particularly, the flute closure 170 can abut the second flow face 130. The flute closure 170 can have a variety of different configurations, but in the current embodiment, the flute closure 170 is a physical barrier such as a glue bead disposed between the first sheet of filter media 150 and the second sheet of filter media 160 towards the second flow face.

An obstruction 172 can be disposed within the coil and outside of the plurality of flutes 140 such that fluids passing through the first flow face 120 and second flow face 130 of the filter assembly 100 must first pass through the filter media 110. Additional obstructions can also be disposed in any other gaps in the filter media to prevent fluid flow therethrough, such as around the outer perimeter of the filter assembly 100 and in a central opening of the filter assembly 100. An obstruction can be formed through depositing an adhesive, such as a glue bead or other barrier at the relevant location.

In various embodiments, including the one depicted, at least one of the first flow face 120 and the second flow face 130 is non-planar. In examples consistent with this particular embodiment, the first flow face 120 is non-planar and the second flow face 130 is non-planar. In particular, the first edge 152 and the third edge 162 (particularly visible in FIG. 4b ) that define the first flow face 120 are non-planar, even though the first edge 152 is planar and the third edge 162 is planar. The second edge 154 and fourth edge 164 that define the second flow face 130 are similarly non-planar, even though the second edge 154 is planar and the fourth edge 164 is planar. In the current embodiment the flute closure 170 is disposed adjacent to the fourth edge 164 of the second sheet of filter media 160 and, as such, the flute closure 170 is generally planar, but in some alternate examples the flute closure 170 is non planar. Similarly, the obstruction 172 is disposed adjacent to the third edge 162 of the second sheet of filter media 160 and so the obstruction 172 is also planar, but in some alternate examples the obstruction 172 is non-planar.

In various embodiments, at least one flute of the plurality of flutes defines an opening that is non-planar, such as a first flute 144 (FIG. 4b ) in this example embodiment. In particular, in the current embodiment all of the plurality of flutes 140 define a non-planar opening, by virtue of the first edge 152 and third edge 162 defining one flute opening and the second edge 154 and fourth edge 164 defining the other flute opening.

FIG. 5 depicts a side cut-away view of yet another example filter assembly 200 consistent with the technology disclosed herein. The filter assembly 200 is constructed of filter media 210 having a first elongate edge 212 defining a first flow face 220, a second elongate edge 214 defining a second flow face 230, and a plurality of flutes 240 extending from the first flow face 220 to the second flow face 230. In the current example, the first flow face 220 is defined on a first end 202 of the filter assembly 200 and the second flow face 230 is defined on a second, opposite end 204 of the filter assembly 200. The first flow face 220 has an axial flow face length L. The first flow face 220 also defines a taper for at least a portion of the axial flow face length from the first end 202 towards the second end 204. In the current example, the taper is relatively constant for at least a portion of the axial flow face length from the first end 202 towards the second end 204.

Similar to the embodiments depicted in FIGS. 3-4 b, the filter assembly 200 is generally constructed to define a fluid pathway 218 between the first flow face 220 and the second flow face 230 through the filter media 210 such that the fluid is filtered by the filter media 210. As such, in this example, each of the plurality of flutes 240 defines a flute opening and a flute closure. Also similar to the embodiments depicted in FIGS. 3-4 b, the filter assembly 200 is constructed of filter media 210 that is in a coiled configuration about a Z-axis. Example filter media 210 configurations consistent with FIG. 5 and other embodiments disclosed herein will be described in more detail below with reference to FIGS. 6a -6 d.

Returning to FIG. 5, each of the plurality of flutes 240 defines a flute distance between the first flow face 220 and the second flow face 230. In the current embodiment, a first flute 244 of the plurality of flutes 240 defines a first flute distance D₁ between the first flow face 220 and the second flow face 230 and a second flute 246 of the plurality of flutes 240 defines a second flute distance D₂ between the first flow face 220 and the second flow face 230. In the current embodiment the first flute distance D₁ is less than the second flute distance D₂, but in other embodiments the first flute distance D₁ is greater than the second flute distance D₂. In a variety of embodiments, the first flute distance D₁ and the second flute distance D₂ differ by greater than 2 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by at least 5 mm, at least 8 mm or even at least 15 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by 3 mm to 20 mm, 10 mm to 20 mm, or 15 mm to 25 mm.

In some embodiments, a third flute 248 of the plurality of flutes 240 defines a third flute distance D₃ between the first flow face 220 and the second flow face 230. In the current embodiment the third flute distance D₃ is greater than the first flute distance D₁ and the second flute distance D₂, but flute distances can have other relative relationships, as has been described above. The third flute distance D₃ will generally differ from at least one of the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. In some embodiments the third flute distance D₃ differs from both the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. The third flute distance D₃ can differ from one or both the first flute distance D₁ and the second flute distance D₂ by similar ranges described above.

In various embodiments, at least one of the first flow face 220 and the second flow face 230 is planar. In examples consistent with this particular embodiment, the first flow face 220 is planar and the second flow face 230 is planar, and the first flow face 220 is non-parallel to the second flow face 230. In some embodiments one or both of the first flow face and the second flow face can be non-planar. For example, one or both of the first flow face and the second flow face can be cut to be a three-dimensional surface.

The filter assembly 200 of FIG. 5 can be constructed from variety of configurations of filter media 210, examples of which are depicted and described in association with FIGS. 6a-6d and also described in general later in this document. Referring first to FIG. 6a , the example filter media 210 is a plurality of sheets of filter media, specifically a first sheet of filter media 250 and a second sheet of filter media 260. The second sheet of filter media 260 is adjacent to the first sheet of filter media 250. The first sheet of filter media 250 and the second sheet of filter media 260 mutually define the plurality of flutes 240. While currently depicted in an uncoiled arrangement, to be consistent with FIG. 5, the filter media 210 is arranged in a coiled configuration about a Z-axis (FIG. 5). Accordingly, each of the first sheet of filter media 250 and the second sheet of filter media 260 are arranged to define a coiled configuration about the Z-axis. As such, the plurality of flutes 240 are also in a coiled configuration about the Z-axis. In this example, the plurality of flutes 240 are generally parallel. In examples consistent with the embodiment of FIG. 6a , the first sheet of filter media 250 is a fluted sheet and the second sheet of filter media 260 is a fluted sheet.

The first sheet of filter media 250 and the second sheet of filter media 260 are generally elongate. In this example, the first sheet of filter media 250 and the second sheet of filter media 260 are continuous and separated by a fold 270. The fold 270 defines the second flow face 230 and the second elongate edge 214 of the filter assembly 200 depicted in FIG. 5. The first sheet of filter media 250 defines a first edge 252 and the second sheet of filter media 260 defines a second edge 262. The first edge 252 and the second edge 262 are configured to mutually define the first flow face 220, and therefore the first elongate edge 212, of the filter assembly 200 (FIG. 3).

In the current example filter media 210, flute openings 242 (visible in FIG. 6a ) of the plurality of flutes 240 is defined at the first flow face 220 (visible in FIG. 5) and a flute closure 270 (visible in FIG. 6a ) is defined towards the second flow face 230 (visible in FIG. 5). In some embodiments, including the one depicted, the flute closure 270 is adjacent to the second flow face 230 (FIG. 5). More particularly, the flute closure 270 can abut the second flow face 230. The flute closure 270 can have a variety of different configurations, but in the embodiment of FIG. 6a , the flute closure 270 is the fold 270 between the first sheet of filter media 250 and the second sheet of filter media 260.

An obstruction 272 can be disposed outside of the plurality of flutes 240 such that fluids passing through the first flow face 220 and second flow face 230 of the filter assembly 200 (FIG. 5) must first pass through the filter media 210. The obstruction can be disposed towards the first elongate edge 212 of the filter media 210 during construction of the filter assembly 200 of FIG. 5. As has been described, additional obstructions can also be disposed in any other gaps in the filter media 210 to prevent fluid flow therethrough, such as around the outer perimeter of the filter assembly 200 and in a central opening of the filter assembly 200. An obstruction can be formed through depositing an adhesive, such as a glue bead at the relevant location.

As has been mentioned, to construct the filter assembly 200 of FIG. 5, the filter media 210 of FIG. 6a is coiled around a Z-axis, and obstructions 272 are disposed in contact with the filter media 210 at relevant locations to elicit the desired fluid flow through the media. In various embodiments, after the filter media 210 is coiled into a cylindrical shape, the filter media 210 is cut to form the desired shape of the first flow face 220. In the embodiment depicted in FIG. 5, the first flow face 220 can be cut with a cutting tool to form a plane that is non-parallel to the second flow face 230. In examples consistent with the current embodiment the second flow face 230 is generally not cut due to the presence of the fold 270, which forms an obstruction that guides fluid flow. The filter media 210 can be cut using laser cutting, in some examples, and in other examples the filter media 210 can be cut using a sharp edge, such as a saw or knife blade. In such embodiments, the obstructions 272 can be disposed in contact with the filter media 210 at locations that will not be cut and removed.

In some alternative embodiments, the first elongate edge 212 of the filter media 210 is cut before being coiled to form the intended shape of the relevant flow face(s) after the filter media 210 is coiled.

FIG. 6b depicts another filter media 210 consistent with the embodiment depicted in FIG. 5 before the filter media is coiled and cut. The filter media 210 is a plurality of sheets of filter media, specifically a first sheet of filter media 257 and a second sheet of filter media 267. The second sheet of filter media 267 is adjacent to the first sheet of filter media 257. The first sheet of filter media 257 and the second sheet of filter media 267 mutually define the plurality of flutes 240 depicted in FIG. 5.

The first sheet of filter media 257 and the second sheet of filter media 267 are generally elongate. In this example, the first sheet of filter media 257 and the second sheet of filter media 267 are discontinuous. The first sheet of filter media 257 defines a first edge 254 and the second sheet of filter media 267 defines a second edge 264. The first edge 254 and the second edge 264 are configured to mutually define the first flow face 220, and therefore the first elongate edge 212, of the filter assembly 200 (FIG. 5). The first sheet of filter media 257 defines a third edge 256 and the second sheet of filter media 267 defines a fourth edge 266. The third edge 256 and the fourth edge 266 are configured to mutually define the second flow face 230, and therefore the second elongate edge 214, of the filter assembly 200 (FIG. 3).

For construction of the filter assembly 200 of FIG. 5, the filter media 210 is arranged in a coiled configuration about a Z-axis (FIG. 5). Accordingly, each of the first sheet of filter media 257 and the second sheet of filter media 267 are arranged to define a coiled configuration about the Z-axis. As such, the plurality of flutes 240 are also in a coiled configuration about the Z-axis. In this example, the plurality of flutes 240 are generally parallel. In examples consistent with the embodiment of FIG. 6b , the first sheet of filter media 257 is a fluted sheet and the second sheet of filter media 267 is also a fluted sheet.

In the current example filter media 210, the flute opening 245 (visible in FIG. 6b ) is defined at the first flow face 220 (visible in FIG. 5) and a flute closure 275 (visible in FIG. 6b in a tear-away section) is defined towards the second flow face 230 (visible in FIG. 5). In some embodiments, including the one depicted in FIG. 6b , the flute closure 275 is adjacent to the second flow face 230 (FIG. 5). More particularly, the flute closure 275 can abut the second flow face 230. The flute closure 275 can have a variety of different configurations, but in the embodiment of FIG. 6b , the flute closure 275 is a physical obstruction, such as a glue bead deposited between the first sheet of filter media 257 and the second sheet of filter media 267.

An obstruction 273 can be disposed outside of the plurality of flutes 240 such that fluids passing through the first flow face 220 and second flow face 230 of the filter assembly 200 (FIG. 5) must first pass through the filter media 210. The obstruction can be disposed towards the first elongate edge 212 of the filter media 210 during construction of the filter assembly 200 of FIG. 5. As has been described, additional obstructions can also be disposed in any other gaps in the filter media 210 to prevent fluid flow therethrough, such as around the outer perimeter of the filter assembly 200 and in a central opening of the filter assembly 200.

The filter media 210 of FIG. 6b can be cut and formed into a filter assembly 200 similarly to the filter media described in FIG. 6a , above.

FIG. 6C depicts yet another filter media 210 consistent with the embodiment depicted in FIG. 5 before the filter media is coiled and cut. The filter media 210 is a plurality of sheets of filter media, specifically a first sheet of filter media 251 and a second sheet of filter media 261. The second sheet of filter media 261 is adjacent to the first sheet of filter media 251. The first sheet of filter media 251 and the second sheet of filter media 261 mutually define the plurality of flutes 240.

The first sheet of filter media 251 and the second sheet of filter media 261 are generally elongate. In this example, the first sheet of filter media 251 and the second sheet of filter media 261 are discontinuous. The first sheet of filter media 251 defines a first edge 253 and the second sheet of filter media 261 defines a second edge 263. The first edge 253 and the second edge 263 are configured to mutually define the first flow face 220, and therefore the first elongate edge 212, of the filter assembly 200 (FIG. 5). The first sheet of filter media 251 defines a third edge 255 and the second sheet of filter media 261 defines a fourth edge 265. The third edge 255 and the fourth edge 265 are configured to mutually define the second flow face 230, and therefore the second elongate edge 214, of the filter assembly 200 (FIG. 5).

For construction of the filter assembly 200 of FIG. 5, the filter media 210 is arranged in a coiled configuration about a Z-axis (FIG. 5). Accordingly, each of the first sheet of filter media 251 and the second sheet of filter media 261 are arranged to define a coiled configuration about the Z-axis. As such, the plurality of flutes 240 are also in a coiled configuration about the Z-axis. In this example, the plurality of flutes 240 are generally parallel. In examples consistent with the embodiment of FIG. 6c , the first sheet of filter media 251 is a fluted sheet and the second sheet of filter media 261 is a facing sheet.

In the current example filter media 210, the flute opening 243 (visible in FIG. 6c ) is defined at the first flow face 220 (visible in FIG. 5), and a flute closure 271 (visible in FIG. 6b in a tear-away section) is defined towards the second flow face 230 (visible in FIG. 5). In some embodiments, including the one depicted in FIG. 6c , the flute closure 271 is adjacent to the second flow face 230 (FIG. 5). More particularly, the flute closure 271 can abut the second flow face 230. The flute closure 271 can have a variety of different configurations, but in the embodiment of FIG. 6c , the flute closure 271 is a physical obstruction, such as a glue bead deposited between the first sheet of filter media 251 and the second sheet of filter media 261.

An obstruction 273 can be disposed outside of the plurality of flutes 240 such that fluids passing through the first flow face 220 and second flow face 230 of the filter assembly 200 (FIG. 5) must first pass through the filter media 210. The obstruction can be disposed towards the first elongate edge 212 of the filter media 210 during construction of the filter assembly 200 of FIG. 5. As has been described, additional obstructions can also be disposed in any other gaps in the filter media 210 to prevent fluid flow therethrough, such as around the outer perimeter of the filter assembly 200 and in a central opening of the filter assembly 200.

The filter media 210 of FIG. 6c can be cut and formed into a filter assembly 200 similarly to the filter media described in FIG. 6a , above.

FIG. 6d is a facing view of a relatively larger elongate segment of the filter media 210 than those depicted in FIGS. 4a-4c to convey an understanding of the general overall shape of the filter media 210 in an uncoiled configuration. FIG. 6d can generally be consistent with the medias depicted in each of FIGS. 6a-6c . FIG. 6d shows that the filter media 210 has a first elongate edge 280, a second elongate edge 282, a first terminal edge 284, and a second terminal edge 286. The first elongate edge 280 corresponds to the first edge of the first sheet of filter media and the second edge of the second sheet of filter media in FIGS. 6a-6c , described above. As such, the first elongate edge 280 also defines the first flow face 220 of the filter assembly (FIG. 5). The second elongate edge 282 can correspond to the fold 270 between the first sheet of filter media and the second sheet of filter media in FIG. 6a , or the third edge of the first sheet of filter media and the fourth edge of the second sheet of filter media of FIGS. 6b -6 c.

The first elongate edge 280 generally forms a sine wave pattern having an increasing or decreasing frequency across the length of the filter media 210. The second elongate edge 282 extends in a generally straight line. Similarly, the first terminal edge 284 and the second terminal edge 286 extend in straight lines, and each are perpendicular to the second elongate edge 282. In the current example, the filter media 210 does not form a trapezoidal shape at least due to the wave pattern of the first elongate edge 280.

Experimental Data

Example configurations generally consistent with the technology disclosed herein were tested in example separator systems and compared to a standard two-stage separator system that is consistent with previous technologies. A cross-sectional view of the standard two-stage separator 2100 is depicted in FIG. 29. The separator 2100 incorporates a pleated, tubular filter media 2156 having an inlet that is formed by an outer cylindrical boundary 2152 of the filter assembly and an outlet 2154 defined within a central opening 2158 of the tubular filter media. Retaining elements 2126 on each end of the separator housing 2110 sealably receive the first end 2151 and second end 2153 of the filter assembly 2150 to direct airflow through the filter media 2156.

Three new designs generally consistent with the present technology were tested against the standard design. The filter assemblies and the separator housings tested were sized similarly. The three filter assemblies consistent with the current disclosure were not tubular filter elements having a radial inlet like in the standard design. Rather, each of the new filter elements were axial flow filters having an inlet flow face having an axial length (as disclosed herein) and some internal seals and support structures for the standard design were not needed for the new designs. Each of the tested filter assemblies consistent with the current disclosure were constructed of filter media having a single-facer media structure, such as depicted and described with reference to FIG. 6C, above, that was coiled about a central axis.

A first new design (referenced as “New No. 1” in the Table, below) was a filter assembly generally consistent with that described with reference to FIG. 2. The filter assembly was installed in a separator housing consistent with that shown and described with reference to FIG. 29, above, where retaining elements were on each end of the separator housing that received the first end and second end (the inlet flow face) of the filter assembly. There was no seal between the retaining element and the inlet flow face of the filter assembly, however. For the second design (referenced as “New No. 2” in the Table, below), the filter assembly was the same as in the first design, but the retaining element on the second end of the separator housing (which received the inlet flow face of the filter assembly in the first new design and the second end of the filter element in the standard design) was removed from the separator housing.

A third new design (referenced as “New No. 3” in the Table, below) was a filter assembly generally consistent with that described with reference to FIG. 2. The filter assembly 2250 was installed in a separator housing 2210 generally consistent with that shown in FIG. 28. Retaining elements consistent with those discussed above with reference to FIG. 29 were omitted. However, the housing 2210 has a centering feature 2290 extending axially from the second end 2214 of the housing 2210 towards the first end 2212 of the housing 2210. The centering feature 2290 engages the distal end of the inlet flow face 2252 to maintain positioning of the distal end of the inlet flow face 2252. Furthermore, the access cover 2270 of the housing 2210 tapered inward towards the central axis z. The inlet and outlet of the separator housing 2210 were enlarged compared to the other tested systems.

The initial pressure drop (dP), the dust on the element after testing (“element gain”), the total dust fed into the system, and the separation efficiency was measured. The air flow rate for each of the tests was set at 4.94 cubic meters per minute. Table 1, below reflects the results:

TABLE 1 dP Element Gain Dust Fed Separation Design (in-H₂O) (g) (g) Efficiency Standard 7.81 421.1 2851 85.52% New No. 1 9.22 280 2589 89.12% New No. 2 9.27 233 2753 91.45% New No. 3 7.08 472 3589 86.85%

The data reflects that, while the New Designs No. 1 and No. 2 had a higher initial pressure drop than the Standard Design, there was an increase in the separation efficiency of the system, which can contribute to a longer filter life. New Design No. 3 had a lower initial pressure drop, but a higher separation efficiency than the Standard Design. New Design No. 3 had a 12% increase in dust on the element compared to the Standard Design, and a 26% increase in the total dust fed into the system relative to the test of the Standard Design.

FIG. 7 depicts another example filter assembly 300 consistent with the technology disclosed herein. The filter assembly 300 is a panel filter assembly. The filter assembly 300 is constructed of filter media 310 defining a first flow face 320, a second flow face 330, and a plurality of flutes 340 extending from the first flow face 320 to the second flow face 330. In the current example of FIG. 7, the first flow face 320 is defined on a first end 302 of the filter assembly 300 and the second flow face 330 is defined on a second, opposite end 304 of the filter assembly 300. In the current example of FIG. 7, the first flow face 320 is non-planar and the second flow face 330 is substantially planar, but in some other embodiments, each of the first flow face 320 and the second flow face 330 can be non-planar. The first flow face 320 has a flow face length L in the Z-direction. In the current example, the first flow face 320 does not define a taper for at least a portion of the axial flow face length from the first end towards the second end.

The filter media 310 is a plurality of sheets of filter media. In particular, the plurality of sheets of filter media has alternating fluted sheets 352 of filter media and alternating facing sheets 354 of filter media. The plurality of sheets of filter media are in a stacked configuration. Each of the plurality of sheets of filter media are discontinuous. Each sheet of filter media has a first edge 312 defining the first flow face 320 of the filter assembly 300. In the current embodiment, each sheet of filter media has a second edge 314 defining the second flow face 330 of the filter assembly 300. The plurality of sheets of filter media cumulatively define the plurality of flutes 340. Each of the plurality of flutes 340 defines a flute opening 342 and a flute closure 370, where an example flute closure 370 is visible where a portion of a facing sheet 354 is torn away from a fluted sheet 352. Each of the plurality of flutes 340 defines a flute distance extending from the first flow face 320 to the second flow face 330. In this example, the plurality of flutes 340 are generally parallel. The plurality of flutes 340 can be upstream flutes or downstream flutes.

The plurality of flutes 340 defined by the plurality of sheets of filter media are arranged in a regularly alternating pattern of flute layers. A first flute layer 350 regularly alternates with a second flute layer 360. The first flute layers 350 each have a first layer distance L₁ between the first flow face 320 and the second flow face 330. Each of the second layers has a second layer distance L₂ between the first flow face 320 and the second flow face 330. In the current example, the first layer distance L₁ is less than the second layer distance L₂, but in other examples, the first layer distance L₁ is greater than the second layer distance L₂. The first layer distance L₁ and the second layer distance L₂ generally differ by greater than 2 mm. In various embodiments, the first layer distance L₁ differs from the second layer distance L₂ by at least 5 mm. In some embodiments, the first layer L₁ differs from the second layer distance L₂ by 3 mm to 20 mm. In some embodiments, the first layer distance L₁ differs from the second layer distance L₂ by at least 8 mm. In some such embodiments, the first layer distance L₁ differs from the second layer distance L₂ by at least 14 mm.

Each individual flute in the first flute layers 350 is defined by a fluted sheet 352 and an adjacent facing sheet 354. Similarly, each of the second layers 360 is defined by a fluted sheet 362 and an adjacent facing sheet 364. In the example of FIG. 7 each fluted sheet and facing sheet in each flute layer define substantially equal distances between the first flow face 320 and the second flow face 330; however, in some embodiments, each fluted sheet and facing sheet in at least one flute layer define distances that differ by greater than 2 mm. Also, in the embodiment of FIG. 7, each flute layer defines a substantially constant distance between the first flow face 320 and the second flow face 330 in the depth direction d (represented in FIG. 7 by an arrow); this means that the distance defined by each flute layer between the first flow face 320 and the second flow face 330 is equal to the flute distance between the first flow face 320 and the second flow face 330 for each flute in the flute layer. In some embodiments, however, the distance defined between the first flow face and the second flow face for one or more sheets of filter media can vary in the depth direction, in which case the flute distances between the first flow face and the second flow face can be used to characterize the flute layers.

In some embodiments, including that depicted in FIG. 7, the plurality of sheets of filter media further defines third flute layers 380 that regularly alternate with the first flute layers 350 and second flute layers 360. Each third flute layer 380 defines a third layer distance L₃ between the first flow face 320 and the second flow face 330. In the current embodiment, the third layer distance L₃ is greater than the first layer distance L₁ and the third layer distance L₃ is less than the second layer distance L₂, although other relative relationships are possible, which has been described. In the presently-depicted example, the third layer distance L₃ differs from the first layer distance L₁ and the second layer distance L₂ by greater than 2 mm.

Furthermore, in the current example of FIG. 7, the plurality of sheets of filter media defines a regularly alternating pattern of fourth flute layers 390, where each fourth flute layer defines a fourth layer distance L₄ between the first flow face 320 and the second flow face 330. The fourth layer distance L₄ is less than each of the first layer distance L₁, the second layer distance L₂, and the third layer distance L₃, although other relative relationships are possible, as previously described. The fourth layer distance L₄ differs from the first layer distance L₁, the second layer distance L₂, and the third layer distance L₃ by greater than 2 mm. Similar to the first flute layers 350 and second flute layers 360, the third flute layers 380 and the fourth flute layers 390 have a fluted sheet 382, 392 and a facing sheet (not visible), respectively. In alternative embodiments, additional or fewer flute layers can be incorporated in filter assemblies consistent with the current technology. While in the current example (and the example discussed with reference to FIG. 9a , below) each regularly alternating layer defines a different distance between the first flow face 320 and the second flow face 330, in some examples two or more regularly alternating layers can define the same distance between the first flow face and the second flow face.

In various embodiments, a filter assembly that has layers and flow faces generally consistent with the description above with respect to FIG. 7 can be incorporated in a two-stage separator system when modified to define a central axis and an outer radial barrier surface between the first flow face and the second flow face. FIG. 8 depicts a schematic cross-sectional view of such a filter assembly 300 a, where the cross-section is perpendicular to the axial direction between the first flow face and the second flow face. The filter assembly 300 a has a central axis Z extending axially between the flow faces, and an outer radial barrier surface 359 extending about the central axis Z between the first flow face such as the inlet flow face and the second flow face such as the outlet flow face (not currently depicted, but similar to as depicted in FIG. 3). At least one of the flow faces (which can be configured to form an inlet flow face in a separator system) has an axial flow face length L (that can be the same as the flow face length in FIG. 7).

To achieve a configuration consistent with FIG. 8, in some examples the sides extending between the first flow face and the second flow face of the panel filter assembly 300 consistent with FIG. 7 can be cut using laser cutting or a sharp edge to form the circular cross-section. To encourage spiraling airflow about the filter element towards the second end of the separator housing (as described above with reference to FIG. 2), a sleeve can define the outer radial barrier surface 359 of the filter assembly 300 a. The sleeve can be consistent with sleeves discussed above with reference to FIG. 2.

The examples depicted and described in association with FIGS. 9A-13, below, also depict panel filter assemblies. Similar to the discussion above with respect to FIG. 8, each of these panel filter assemblies can be configured to be incorporated in a two-stage separator system by (1) configuring the sides of the panels between the flow faces to form a circular cross-sectional shape having a central axis and (2) incorporating a sleeve (for example) to define an outer radial barrier surface extending between the inlet flow face and the outlet flow face. In such embodiments, at least one flow face has an axial length.

FIG. 9a depicts a perspective view of another example filter assembly 400 consistent with the technology disclosed herein, and FIG. 9b depicts a facing view at a first flow face 420 of the example filter assembly 400. The filter assembly 400 is a panel filter assembly. The filter assembly 400 is constructed of filter media 410 defining the first flow face 420, a second flow face 430, and a plurality of flutes 440 extending from the first flow face 420 to the second flow face 430 in an axial direction. The first flow face 420 is defined on a first end 402 of the filter assembly 400 and the second flow face 430 is defined on a second, opposite end 404 of the filter assembly 400. In the current example of FIG. 8, both the first flow face 420 is non-planar and the second flow face 430 is non-planar, but in some other embodiments, only one of the first flow face 420 and the second flow face 430 is non-planar and the other of the first flow face 420 and the second flow face 430 is planar. Each of the first flow face 420 and the second flow face 430 has a flow face length L_(A1), L_(A2), respectively. Neither the first flow face 420 nor the second flow face 430 define a taper for at least a portion of its respective axial flow face length.

The filter media 410 is a plurality of sheets of filter media. In particular, the plurality of sheets of filter media has fluted sheets of filter media. The plurality of sheets of filter media are in a stacked configuration. The plurality of sheets of filter media are continuous relative to each other. Each sheet of filter media has a first fold 412 defining the first flow face 420 of the filter assembly 400. In the current embodiment, each sheet of filter media has a second fold 414 defining the second flow face 430 of the filter assembly 400. The plurality of sheets of filter media 410 cumulatively define the plurality of flutes 440. Each of the plurality of flutes 440 defines a flute opening 442 and a flute closure 470, where the flute closures 470 are defined between pairs of the first folds 412 at the first flow face 420 and pairs of the second folds 414 at the second flow face 430. In some alternative embodiments the flute closure can be defined by a single fold line that separates adjacent sheets of filter media. In this example, the plurality of flutes 440 are generally parallel. The plurality of flutes 440 can be upstream flutes or downstream flutes.

The plurality of sheets of filter media define a regularly alternating pattern of first flute layers 450 and second flute layers 460. The first flute layers 450 each have a first layer distance L₁ between the first flow face 420 and the second flow face 430. Each of the second flute layers 460 has a second layer distance L₂ between the first flow face 420 and the second flow face 430. The second layer distance L₂ is less than the first layer distance L₁ in the current example, although in some embodiments the second layer distance L₂ is greater than the first layer distance L₁. The first layer distance L₁ and the second layer distance L₂ generally differ by greater than 2 mm. In various embodiments, the first layer distance L₁ differs from the second layer distance L₂ by at least 5 mm. In some embodiments, the first layer L₁ differs from the second layer distance L₂ by 4 mm to 20 mm. In some embodiments, the first layer distance L₁ differs from the second layer distance L₂ by at least 8 mm. In some such embodiments, the first layer distance L₁ differs from the second layer distance L₂ by at least 14 mm.

Each of the first flute layers 450 is defined by a first fluted sheet 452 and an adjacent second fluted sheet 454. Similarly, each of the second flute layers 460 is defined by a third fluted sheet 462 and an adjacent fourth fluted sheet 464. Similar to the embodiment described above with respect to FIG. 7, in the current embodiment of FIG. 9 a, each flute layer defines a substantially constant distance between the first flow face 420 and the second flow face 430 in the depth direction d2; this means that the distance defined by each flute layer is equal to the flute distance between the first flow face 420 and the second flow face 430 of each flute in the flute layer. In some embodiments, however, the distance that one or more sheets of filter media defines between the first flow face 420 and the second flow face 430 can vary in the depth direction d₂.

Additional alternating flute layers can be incorporated into filter assemblies consistent with the technology disclosed herein, similar to the previous example reflected in FIG. 7.

FIG. 10 depicts a perspective view of yet another example filter assembly 700 consistent with the technology disclosed herein. The filter assembly 700 is a panel filter that is constructed of a plurality of sheets of filter media 710 in a stacked configuration that cumulatively define a first plurality of flutes 740, a first flow face 720 and a second flow face 730 opposite the first flow face relative to the filter assembly 700. The plurality of stacked sheets of filter media 710 are alternating fluted sheets of filter media and facing sheets of filter media. The plurality of stacked sheets of filter media 710 are discontinuous. In various embodiments, at least one of the first flow face 720 and the second flow face 730 is non-planar. In the current example, the first flow face 720 defines a flow face length L. The first flow face 720 defines a taper for at least a portion of the axial flow face length L. The taper increases for at least a portion of the axial flow face length and the taper continuously changes along the axial flow face length.

Each of the first plurality of flutes 740 defines a flute opening 742 at the first flow face 720 and a flute closure 744 towards the second flow face 730. In some embodiments, at least one flute 745 of the plurality of flutes 740 defines a flute opening 742 that is non-planar. Each of the first plurality of flutes 740 defines a flute distance from the first flow face 720 to the second flow face 730. Each sheet of filter media 710 can be characterized as having a width extending in a direction parallel to an x-axis and a length extending in a direction parallel to a z-axis. The plurality of sheets of filter media 710 are stacked in a direction parallel to a y-axis.

In a number of embodiments, the filter assembly 700 at least has a first sheet of filter media 750 and a second sheet of filter media 760 mutually defining the first flow face 720, the second flow face 730, and a portion of the first plurality of flutes 740. In this example the first sheet of filter media 750 is a fluted sheet and the second sheet of filter media 760 is a facing sheet. A first flute 741 of the first plurality of flutes 740 defines a first flute distance d₁ and a second flute 743 of the first plurality of flutes 740 defines a second flute distance d₂. In the current example, the first flute distance d₁ is greater than the second flute distance d₂, although in some other examples, the first flute distance d₁ is less than the second flute distance d₂. The first flute distance d₁ and the second flute distance d₂ differ by greater than 2 mm. In some embodiments the first flute distance d₁ and the second flute distance d₂ differ by at least 5 mm. In some embodiments the first flute distance d₁ and the second flute distance d₂ differ by 3 mm to 20 mm. In some embodiments the first flute distance d₁ and the second flute distance d₂ differ by at least 8 mm. In some embodiments the first flute distance d₁ and the second flute distance d₂ differ by at least 15 mm.

The filter assembly 700 also has a third sheet of filter media 770, where the third sheet of filter media and the second sheet of filter media 760 mutually define a second plurality of flutes 780, the first flow face 720 and the second flow face 730. Each of the second plurality of flutes 780 extends from the first flow face 720 to the second flow face 730. Each of the second plurality of flutes 780 defines a flute opening at the second flow face 730 (not visible in this view) and a flute closure towards the first flow face 720. The flute closure can be an obstruction disposed between the second sheet of filter media 760 and the third sheet of filter media 770 towards the first flow face 720. The second plurality of flutes 780 can have a third flute 747 that defines a third flute distance d₃ between the first flow face 720 and the second flow face 730. In the current example, the third flute distance d₃ is greater than the first flute distance d₁ and the second flute distance d₂, although alternate relative relationships among the flute distances are contemplated, as well, which has been previously discussed. The first flute distance d₁ differs from the third flute distance d₃ by greater than 2 mm. In some embodiments, each of the first flute distance d₁, second flute distance d₂, and third flute distance d₃ differ by greater than 2 mm. In some embodiments the first flute distance d₁ differs from the second flute distance d₂ and the third flute distance d₃ by amounts and ranges previously described herein.

In the current example of FIG. 10, the second flute 743 is adjacent the first flute 741 in the x-axis direction, although in some other embodiments the second flute 743 is not adjacent the first flute 741. In some embodiments, the third flute 747 is positioned relative to the first flute 741 in the y-axis direction, but in other embodiments the third flute 747 is not positioned relative to the first flute 741 in the y-axis direction. In some alternative embodiments the third flute 747 can be a flute in the first plurality of flutes 740.

In the current example, the first flow face 720 is non-planar and the second flow face 730 is planar. In an alternative example embodiment, both the first flow face and the second flow face are non-planar. In some embodiments, the first flow face and the second flow face are planar and non-parallel to each other. In various embodiments, the plurality of flutes 740 are parallel, although in some embodiments, the plurality of flutes 740 are not parallel.

Similar to the embodiments depicted in FIGS. 3-4 b, the filter assembly 700 is generally constructed to define a fluid pathway 718 between the first flow face 720 and the second flow face 730 through the filter media 710 such that the fluid is filtered by the filter media 710.

In various embodiments, at least one of the first flow face 720 and the second flow face 730 is planar. In examples consistent with the particular embodiment of FIG. 10, the first flow face 720 is planar and the second flow face 730 is planar, and the first flow face 720 is non-parallel to the second flow face 730. In alternative embodiments one or both of the first flow face and the second flow face can be non-planar. For example, one or both of the first flow face and the second flow face can be cut to be a three-dimensional surface.

FIG. 11 depicts a perspective view of yet another example filter assembly 800 consistent with the technology disclosed herein. The filter assembly 800 is a panel filter that is constructed of a plurality of sheets of filter media 810 in a stacked configuration that define a first plurality of flutes 840, a first flow face 820 and a second flow face 830 opposite the first flow face relative to the filter assembly 800. The plurality of stacked sheets of filter media 810 are fluted sheets of filter media. The plurality of stacked sheets of filter media 810 are discontinuous. In various embodiments, at least one of the first flow face 820 and the second flow face 830 is non-planar, and in the current embodiment, both the first flow face 820 and the second flow face 830 are non-planar. Each of the first flow face 820 and the second flow face 830 has an axial flow face length (see L, for example). Each of the first flow face 820 and the second flow face 830 defines a taper in the axial direction.

The plurality of sheets of filter media 810 cumulatively define a plurality of flutes 840. Each of the first plurality of flutes 840 defines a flute opening 842 at the first flow face 820 and a flute closure (not shown) towards the second flow face 830, where the flute closure is similar to those described above and depicted at least in FIGS. 4a and 6b . In some embodiments, at least one flute 845 of the plurality of flutes 840 defines a flute opening 842 that is non-planar. Each of the first plurality of flutes 840 defines a flute distance from the first flow face 820 to the second flow face 830. Each sheet of filter media 810 can be characterized as having a width extending in a direction parallel to an x-axis and a length extending in a direction parallel to a z-axis. The plurality of sheets of filter media 810 are stacked in a direction parallel to a y-axis.

In a number of embodiments, the filter assembly 800 at least has a first sheet of filter media 850 and a second sheet of filter media 860 mutually defining the first flow face 820, the second flow face 830, and a portion of the first plurality of flutes 840. In this example both the first sheet of filter media 850 and the second sheet of filter media 860 are fluted sheets. A first flute 841 of the portion of the first plurality of flutes 840 defines a first flute distance d₁ and a second flute 843 of the first plurality of flutes 840 defines a second flute distance d₂. In the current example, the first flute distance d₁ is greater than the second flute distance d₂, although in some other examples, the first flute distance d₁ is less than the second flute distance d₂. The first flute distance d₁ and the second flute distance d₂ differ by greater than 2 mm and can further differ by amounts and ranges previously discussed.

The filter assembly 800 also has a third sheet of filter media 870, where the third sheet of filter media and the second sheet of filter media 860 mutually define a second plurality of flutes 880, the first flow face 820 and the second flow face 830. Each of the second plurality of flutes 880 extends from the first flow face 820 to the second flow face 830. Each of the second plurality of flutes 880 defines a flute opening at the second flow face 830 (not visible in this view) and a flute closure towards the first flow face 820. The flute closure can be an obstruction disposed between the second sheet of filter media 860 and the third sheet of filter media 870 towards the first flow face 820.

The second plurality of flutes 880 can have a third flute 847 that defines a third flute distance d₃ between the first flow face 820 and the second flow face 830. In the current example, the third flute distance d₃ is greater than the first flute distance d₁ and the second flute distance d₂, although alternate relative relationships among the flute distances are contemplated. The first flute distance d₁ differs from the third flute distance d₃ by greater than 2 mm. In some embodiments, each of the first flute distance d₁, second flute distance d₂, and third flute distance d₃ differ by greater than 2 mm. In some embodiments the first flute distance d₁ differs from the second flute distance d₂ and the third flute distance d₃ by amounts and ranges previously described herein.

In the current example the second flute 843 is adjacent the first flute 841 in the x-axis direction, although in some other embodiments the second flute 843 is not adjacent the first flute 841. In some embodiments, the third flute 847 is positioned relative to the first flute 841 in the y-axis direction, but in other embodiments the third flute 847 is not positioned relative to the first flute 841 in the y-axis direction. In some alternative embodiments the third flute 847 can be a flute in the first plurality of flutes 840.

In the current example, the first flow face 820 is non-planar and the second flow face 830 is non-planar. In particular, the first flow face 820 is recessed relative to the filter assembly 800. Similarly, the second flow face 830 is recessed relative to the filter assembly. In an alternative example, both the first flow face and the second flow face are planar and non-parallel to each other. In some embodiments, the first plurality of flutes 840 are parallel, although in some embodiments, the first plurality of flutes 840 are not parallel.

Similar to the embodiments described above, the filter assembly 800 is generally constructed to define a fluid pathway 818 between the first flow face 820 and the second flow face 830 through the filter media 810 such that the fluid is filtered by the filter media 810.

The example filter assemblies described and depicted in FIGS. 9 and 10 can be constructed through a variety of different approaches. In at least one embodiment, flute obstructions are deposited between the adjacent sheets of filter media at relevant locations and the sheets of filter media are stacked. The stacked media is then cut with a cutting tool (examples of which have been mentioned above with respect FIG. 5) to form the first flow face and/or the second flow face into the desired configuration. In an alternative embodiment, the edges of the sheets of filter media corresponding to flow faces are cut to the desired configuration, and the cut sheets of media are then stacked to form into a filter assembly. The flute obstructions can be deposited on the sheets of filter media before or after the sheets of filter media are cut.

FIG. 12 depicts a perspective view of yet another example filter assembly 900 consistent with the technology disclosed herein. The filter assembly 900 is a panel filter that is constructed of a plurality of sheets of filter media 910 in a stacked configuration that define a first plurality of flutes 940, a first flow face 920 of the filter assembly 900 and a second flow face 930 opposite the first flow face 920 relative to the filter assembly 900. The plurality of sheets of filter media 910 are fluted sheets of filter media. In various embodiments, at least one of the first flow face 920 and the second flow face 930 is non-planar, and in the current embodiment, the first flow face 920 is non-planar and the second flow face 930 is planar. The first flow face 920 has an axial flow face length L extending in an axial direction Z. The first flow face 920 defines a taper for at least a portion of the axial flow face length.

The plurality of sheets of filter media 910 are continuous relative to each other. Each sheet of filter media has a first fold 912 defining the first flow face 920 of the filter assembly 900. Each sheet of filter media 910 has a second fold 914 (only a small portion of which is visible) defining the second flow face 930 of the filter assembly 900. Each of the first plurality of flutes 940 defines a flute opening 942 at the first flow face 920 and a flute closure 916 towards the second flow face 930. The flute closure 916 is defined by the filter media on the second flow face 930, where the filter media extends between adjacent second folds 914 on the second flow face 930.

In some embodiments, at least one flute 945 of the plurality of flutes 940 defines a flute opening 942 that is non-planar. Each of the first plurality of flutes 940 defines a flute distance from the first flow face 920 to the second flow face 930. Each sheet of filter media 910 can be characterized as having a width extending in a direction parallel to an x-axis and a length extending in a direction parallel to a z-axis. The plurality of sheets of filter media 910 are stacked in a direction parallel to a y-axis.

In a number of embodiments, the filter assembly 900 at least has a first sheet of filter media 950 and a second sheet of filter media 960 mutually defining the first flow face 920, the second flow face 930, and a portion of the first plurality of flutes 940. In this example both the first sheet of filter media 950 and the second sheet of filter media 960 are fluted sheets. A first flute 941 of the portion of the first plurality of flutes 940 defines a first flute distance d₁ and a second flute 943 of the first plurality of flutes 940 defines a second flute distance d₂. In the current example, the first flute distance d₁ is less than the second flute distance d₂, although in some other examples, the first flute distance d₁ is greater than the second flute distance d₂. The first flute distance d₁ and the second flute distance d₂ differ by greater than 2 mm and can further differ by amounts and ranges previously discussed.

The filter assembly 900 also has a third sheet of filter media 970, where the third sheet of filter media and the second sheet of filter media 960 mutually define a second plurality of flutes 980, the first flow face 920 and the second flow face 930. Each of the second plurality of flutes 980 extends from the first flow face 920 to the second flow face 930. Each of the second plurality of flutes 980 defines a flute opening at the second flow face 930 (not visible in this view) and a flute closure 916 towards the first flow face 920. The flute closure can be an obstruction disposed between the second sheet of filter media 960 and the third sheet of filter media 970 towards the first flow face 920. In the current embodiment the flute closure 916 is a portion of filter media defined by one or more folds 912, similar to as described with respect to FIGS. 9a and 9b . The second plurality of flutes 980 can have a third flute 981 that defines a third flute distance d₃ between the first flow face 920 and the second flow face 930. In the current example, the third flute distance d₃ is greater than the first flute distance d₁ and the second flute distance d₂ (although not clear from the current viewing angle), although alternate relative relationships among the flute distances are contemplated. The first flute distance d₁ differs from the third flute distance d₃ by greater than 2 mm. In some embodiments, each of the first flute distance d₁, second flute distance d₂, and third flute distance d₃ differ by greater than 2 mm. In some embodiments the first flute distance d₁ differs from the second flute distance d₂ and the third flute distance d₃ by amounts and ranges previously described herein.

In the current example of FIG. 12, the second flute 943 is adjacent the first flute 941 in the x-axis direction, although in some other embodiments the second flute 943 is not adjacent the first flute 941. In some embodiments, the third flute 981 is positioned relative to the first flute 941 in the y-axis direction, but in other embodiments the third flute 981 is not positioned relative to the first flute 941 in the y-axis direction. In some alternative embodiments the third flute 981 can be a flute in the first plurality of flutes 940.

In the current example of FIG. 12, the first flow face 920 is non-planar and the second flow face 930 is planar. In an alternative example embodiment, both the first flow face and the second flow face are planar and non-parallel to each other. In some embodiments, the first plurality of flutes 940 are parallel, although in some alternative embodiments, the first plurality of flutes 940 are not parallel. Also, while in the current embodiment the filter media is pleated, in some other embodiments the media is not pleated.

Similar to the embodiments described above, the filter assembly 900 is generally constructed to define a fluid pathway 918 between the first flow face 920 and the second flow face 930 through the filter media 910 such that the fluid is filtered by the filter media 910.

FIG. 13 depicts a perspective view of yet another example filter assembly 1000 consistent with the technology disclosed herein. The filter assembly 1000 is a panel filter that is constructed of a plurality of sheets of filter media 1010 in a stacked configuration that define a first plurality of flutes 1040, a first flow face 1020 of the filter assembly 1000 and a second flow face 1030 opposite the first flow face 1020 relative to the filter assembly 1000. The plurality of sheets of filter media 1010 are fluted sheets of filter media. In the current embodiment, the first flow face 1020 is planar and the second flow face 1030 is planar, and the first flow face 1020 is non-parallel to the second flow face 1030. The first flow face 1020 has a flow face length L. The first flow face 1020 defines a taper for at least a portion of the axial flow face length.

The plurality of sheets of filter media 1010 are continuous relative to each other. Each sheet of filter media has a first fold 1012 defining the first flow face 1020 of the filter assembly 1000. Each sheet of filter media 1010 has a second fold 1014 (only a small portion of which is visible) defining the second flow face 1030 of the filter assembly 1000. Each of the first plurality of flutes 1040 defines a flute opening 1042 at the first flow face 1020 and a flute closure 1016 towards the second flow face 1030. The flute closure 1016 is defined by the filter media on the second flow face 1030, where the filter media extends between adjacent second folds 1014 on the second flow face 1030. The flute closure 1016 can be similar to that described in the discussion of FIGS. 9a and 9 b.

Each of the first plurality of flutes 1040 defines a flute distance from the first flow face 1020 to the second flow face 1030. Each sheet of filter media 1010 can be characterized as having a width extending in a direction parallel to an x-axis and a length extending in a direction parallel to a z-axis. The plurality of sheets of filter media 1010 are stacked in a direction parallel to a y-axis.

In a number of embodiments, the filter assembly 1000 at least has a first sheet of filter media 1050 and a second sheet of filter media 1060 mutually defining the first flow face 1020, the second flow face 1030, and a portion of the first plurality of flutes 1040. In this example both the first sheet of filter media 1050 and the second sheet of filter media 1060 are fluted sheets. A first flute 1041 of the portion of the first plurality of flutes 1040 defines a first flute distance d₁ and a second flute 1043 of the first plurality of flutes 1040 defines a second flute distance d₂. In the current example, the first flute distance d₁ is less than the second flute distance d₂, although in some other examples, the first flute distance d₁ is greater than the second flute distance d₂. The first flute distance d₁ and the second flute distance d₂ differ by greater than 2 mm and can further differ by amounts and ranges previously discussed.

The filter assembly 1000 also has a third sheet of filter media 1070, where the third sheet of filter media and the second sheet of filter media 1060 mutually define a second plurality of flutes 1080, the first flow face 1020 and the second flow face 1030. Each of the second plurality of flutes 1080 extends from the first flow face 1020 to the second flow face 1030. Each of the second plurality of flutes 1080 defines a flute opening at the second flow face 1030 (not visible in this view) and a flute closure 1016 towards the first flow face 1020. The flute closure can be an obstruction disposed between the second sheet of filter media 1060 and the third sheet of filter media 1070 towards the first flow face 1020. In the current embodiment the flute closure 1016 is a portion of filter media defined by one or more folds 1012.

The second plurality of flutes 1080 can have a third flute 1081 that defines a third flute distance d₃ between the first flow face 1020 and the second flow face 1030. In the current example, the third flute distance d₃ is less than the first flute distance d₁ and the second flute distance d₂, but in some embodiments the third flute distance d₃ is greater than one or both of the first flute distance d₁ and the second flute distance d₂ The first flute distance d₁ differs from the third flute distance d₃ by greater than 2 mm. In some embodiments, each of the first flute distance d₁, second flute distance d₂, and third flute distance d₃ differ by greater than 2 mm. In some embodiments the first flute distance d₁ differs from the second flute distance d₂ and the third flute distance d₃ by amounts and ranges previously described herein.

In the current example of FIG. 13, the second flute 1043 is adjacent the first flute 1041 in the x-axis direction, although in some other embodiments the second flute 1043 is not adjacent the first flute 1041. In some embodiments, the third flute 1081 is positioned relative to the first flute 1041 in the y-axis direction, but in other embodiments the third flute 1081 is not positioned relative to the first flute 1041 in the y-axis direction. In some alternative embodiments the third flute 1081 can be a flute in the first plurality of flutes 1040.

In some embodiments, the first plurality of flutes 1040 are parallel, although in some embodiments, the first plurality of flutes 1040 are not parallel. Also, while in the current embodiment the filter media is pleated, in some other embodiments the pleated media is not pleated and obstructions are positioned between sheets of filter media to close off ends of flutes.

Similar to the embodiments described above, the filter assembly 1000 is generally constructed to define a fluid pathway 1018 between the first flow face 1020 and the second flow face 1030 through the filter media 1010 such that the fluid is filtered by the filter media 1010.

FIG. 14A depicts one example filter assembly consistent with the technology disclosed herein. The filter assembly 500 is constructed of filter media 510 defining a first flow face 520, a second flow face 530, and a plurality of flutes 540 extending from the first flow face 520 to the second flow face 530 in an axial direction Z. In the current example, the first flow face 520 is defined on a first end 502 of the filter assembly 500 and the second flow face 530 is defined on a second, opposite end 504 of the filter assembly 500. The first flow face 520 has an axial flow face length L and defines a taper for at least a portion of the axial flow face length.

The filter media 510 is a plurality of sheets of filter media, specifically a first sheet of filter media 512 and a second sheet of filter media 514. The second sheet of filter media 514 is visible in FIG. 14B, which depicts a portion of the filter media 510 in a flat, uncoiled arrangement, distinguished from the coiled filter media 510 in the filter assembly 500 consistent with FIG. 14A. FIG. 14B is a facing view of the second sheet of filter media 514. The second sheet of filter media 514 is adjacent to the first sheet of filter media 512. The first sheet of filter media 512 and the second sheet of filter media 514 mutually define the plurality of flutes 540. The filter media 510 defines a coiled configuration about a Z-axis. Accordingly, each of the first sheet of filter media 512 and the second sheet of filter media 514 defines a coiled configuration around the Z-axis. As such, the plurality of flutes 540 are also in a coiled configuration about the Z-axis.

In the current example, the first sheet of filter media 512 and the second sheet of filter media 514 are coiled about a rod 585. As such, the rod 585 extends centrally through the filter assembly 500. The rod 585 has a proximal end positioned towards the second flow face 530 and a distal end positioned towards the first flow face 520, where the second flow face 530 can be an outlet flow face and the first flow face 520 can be an inlet flow face 520. The rod 585 defines a handle 586 on the distal end that is configured to be grasped by a user during installation and removal of the filter assembly 500 in a two-stage separator system (see. FIGS. 1 and 2). In such embodiments, the separator system can define a centering feature that is configured to receive the handle 586, such as described above with reference to FIG. 2. In some embodiments the handle can be omitted from the filter element. In some embodiments both the handle and the rod is omitted from the filter element.

As visible in FIG. 14B, the filter media 510 (particularly the first sheet of filter media 512 and the second sheet of filter media 514) are generally elongate, which enables the first sheet of filter media 512 and the second sheet of filter media 514 to be coiled about the Z-axis to form a filter assembly. In this example, the first sheet of filter media 512 and the second sheet of filter media 514 are discontinuous. The first sheet of filter media 512 defines a first edge 511 and a second edge 513 (FIG. 14A). The second sheet of filter media 514 defines a third edge 515 and a fourth edge 517 (FIG. 14B). The first edge 511 and the third edge 515 mutually define the first flow face 520 of the filter assembly 500. The second edge 513 and the fourth edge 517 mutually define the second flow face 530 of the filter assembly 500. The first edge 511 and third edge 515 each individually form an undulating or wavy line. The second edge 513 and the fourth edge 517 each individually form a straight line. The filter media 510 in examples consistent with the current embodiment has four edges. The shape of the filter media 510 is generally non-rectangular and non-trapezoidal due to the undulating/wavy edge. In particular, the first edge 511 and third edge 515 mutually define multiple concave and convex shapes.

In examples consistent with the current embodiment, the first sheet of filter media 512 is fluted, and the second sheet of filter media 514 is a facing sheet. In the current embodiment the plurality of flutes are parallel, but in some other embodiments the plurality of flutes are not parallel.

The filter assembly 500 is generally constructed to define a fluid pathway 506 between the first flow face 520 and the second flow face 530 through the filter media 510 such that the fluid is filtered by the filter media 510. In particular, the plurality of flutes 540 defines either inlet flutes, or outlet flutes, similar to as described in FIG. 3.

Each of the plurality of flutes 540 defines a flute opening 542 and a flute closure (not visible). The flute opening 542 forms an end-most portion of the fluid pathway 506 along the flutes to accommodate fluid flow into or out of the filter assembly 500. The flute closure obstructs fluid flow along the flute, thereby defining a portion of the fluid pathway 506 through the filter media 510. So, for example, a plurality of inlet flutes can define the flute opening 542 at the first flow face 520 and a flute closure is defined across the plurality of inlet flutes towards the second flow face 530. In some embodiments, the flute closure is adjacent to the second flow face 530. More particularly, the flute closure can abut the second flow face 530. The flute closure can be similar to flute closures discussed above.

In the current embodiment, the volume defined between an outer surface 516 of the first sheet of filter media 512 (FIG. 14A) and an outer surface 518 of the second sheet of filter media 514 (FIG. 14B) when the filter media is coiled (FIG. 14A) defines a fluid pathway 506 that is not necessarily characterized as being defined by a plurality of flutes.

An obstruction can be disposed within the coil and outside of the plurality of flutes 540 such that fluids passing through the first flow face 520 and second flow face 530 of the filter assembly 500 must first pass through the filter media 510. Additional obstructions can also be disposed in any other gaps in the filter media to prevent fluid flow there-through, such as around the outer perimeter of the filter assembly 500 and in a central opening of the filter assembly 500. An obstruction can be formed through depositing an adhesive, such as a glue bead at the relevant location.

Each of the plurality of flutes 540 defines a flute distance between the first flow face 520 and the second flow face 530. In the current embodiment, a first flute 544 of the plurality of flutes 540 defines a first flute distance D₁ between the first flow face 520 and the second flow face 530 and a second flute 546 of the plurality of flutes 540 defines a second flute distance D₂ between the first flow face 520 and the second flow face 530. In some examples, the first flute distance D₁ is less than the second flute distance D₂, as currently depicted. In some other examples, the first flute distance D₁ is greater than the second flute distance D₂. In certain embodiments, the first flute distance D₁ and the second flute distance D₂ differ by greater than 2 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by at least 5 mm, at least 8 mm or even at least 15 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by 3 mm to 520 mm, 510 mm to 520 mm, or 15 mm to 25 mm.

In some embodiments, a third flute 548 of the plurality of flutes 540 defines a third flute distance D₃ between the first flow face 520 and the second flow face 530. The third flute distance D₃ will generally differ from at least one of the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. In some embodiments the third flute distance D₃ differs from both the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. The third flute distance D₃ can differ from one or both the first flute distance D₁ and the second flute distance D₂ by similar ranges described above. In the current example, the third flute distance D₃ is greater than the first flute distance D₁ and less than the second flute distance D₂.

The differences in flute distances between the first flow face 520 of the filter assembly 500 and the second flow face 530 of the filter assembly 500 is also evidenced by the shapes of the flow faces relative to each other. In various embodiments, at least one of the first flow face 520 and the second flow face 530 is non-planar. In various embodiments, at least one of the first flow face 520 and the second flow face 530 is substantially planar. In examples consistent with this particular embodiment, the first flow face 520 is non-planar and the second flow face 530 is planar. Further, in this particular embodiment, the first flow face 520 is configured such that it protrudes outward from the filter assembly in the axial direction Z. The shape of the first flow face 520 is generally asymmetric relative to the Z-axis.

FIGS. 26a and 26b depict example cross-sections of an example filter assembly 500 installed in a housing similar to the housing 1910 depicted in FIGS. 1-2, where the cross-sections are perpendicular to a z-axis that is central to the housing 1910 and the filter assembly 500. The filter assembly 500 has a first flow face 520 that does not reflect flute profile shapes. FIG. 26a is a first cross section taken at a first position P₁ along the axial length of the first flow face 520 and FIG. 26b is a second cross section taken at a second position P₂ along the axial length of the first flow face 520. The annulus defined between the first flow face 520 and the housing 1910 in a cross-section perpendicular to the z-axis has an increasing area A along at least a portion of the length of the first flow face 520 from a first side to the second side of the housing 1910. In particular, the area of the annulus A₁ defined between first flow face 520 and the housing 1910 in FIG. 26a at position P₁ is less than the area of the annulus A₂ at position P₂.

Furthermore, the radial distances R_(1,2) defined between the first flow face 520 and the housing 1910 relative to the central axis z at the first position P₁ and the second position P₂ along the axial length of the inlet flow face 520 are different. The second radial distance R₂ is greater than the first radial distance R₁, where the first radial distance R₁ and the second radial distance R₂ are in axial alignment and in parallel.

It will be appreciated that, in some alternative embodiments, the first flow face 520 can be planar and the second flow face 530 can be non-planar. In some embodiments at least one flute in the plurality of flutes 540 defines a flute opening that is non-planar.

In examples consistent with the current embodiment, an obstruction 549 is disposed adjacent to the fourth edge 517 of the second sheet of filter media 514 along the length of the second sheet of filter media 514. The fourth edge 517 of the second sheet of filter media 514 is generally planar when the filter media 510 is in a coiled configuration. Here the obstruction 549 also is generally planar when the filter media 510 is in a coiled configuration.

FIG. 15A depicts an example filter assembly 550 consistent with the technology disclosed herein, and FIG. 15B depicts a facing view of corresponding filter media 560, which is in an uncoiled, or planar arrangement. The filter assembly 550 is constructed of filter media 560 defining a first flow face 570, a second flow face 580, and a plurality of flutes 590 extending from the first flow face 570 to the second flow face 580. In the current example, the first flow face 570 is defined on a first end 552 of the filter assembly 550 and the second flow face 580 is defined on a second, opposite end 554 of the filter assembly 550. The first flow face 570 has an axial flow face length L and the first flow face 570 defines a taper for at least a portion of the axial flow face length L.

The filter media 560 is a plurality of sheets of filter media, specifically a first sheet of filter media 562 and a second sheet of filter media 564. The second sheet of filter media 564 is visible in FIG. 15B, which is a portion of the filter media 560 in a flat, uncoiled arrangement, distinguished from the coiled filter media 560 forming the filter assembly 550 consistent with FIG. 15A. FIG. 15B is a facing view of the second sheet of filter media 564. The second sheet of filter media 564 is adjacent to the first sheet of filter media 562. The first sheet of filter media 562 and the second sheet of filter media 564 mutually define the plurality of flutes 590. The filter media 562 can have a variety of configurations, some examples of which are described in association with FIGS. 6a-6d , and also described below. In the current embodiment the plurality of flutes are parallel, but in some other embodiments the plurality of flutes are not parallel.

The filter media 560 defines a coiled configuration about a Z-axis. Accordingly, each of the first sheet of filter media 562 and the second sheet of filter media 564 defines a coiled configuration around the Z-axis. As such, the plurality of flutes 590 are also in a coiled configuration about the Z-axis.

As visible in FIG. 15B, the filter media 560 (particularly the first sheet of filter media 562 and the second sheet of filter media 564) are generally elongate, which enables the first sheet of filter media 562 and the second sheet of filter media 564 to be coiled about the Z-axis to form a filter assembly. In this example, the first sheet of filter media 562 and the second sheet of filter media 564 can be continuous or discontinuous. In embodiments where the sheets are discontinuous, the first sheet of filter media 562 defines a first edge 561 and a second edge 563 (FIG. 15A) and the second sheet of filter media 564 defines a third edge 565 and a fourth edge 567 (FIG. 15B). The first edge 561 and the third edge 565 mutually define the first flow face 570 of the filter assembly 550. The second edge 563 and the fourth edge 567 mutually define the second flow face 580 of the filter assembly 550. The second edge 593 and the fourth edge 567 each individually form a straight line that defines the edge of the filter media 564.

The first edge 561 and third edge 565 mutually and individually form a stepped line. The stepped line has horizontal segments 572 joined by vertical segments 574. The shape of the filter media 564 is generally non-rectangular and non-trapezoidal based on the stepped edge.

The filter assembly 550 is generally constructed to define a fluid pathway 556 between the first flow face 570 and the second flow face 580 through the filter media 560 such that the fluid is filtered by the filter media 560. In particular, the plurality of flutes 590 defines either inlet flutes or outlet flutes, similar to as described above.

Each of the plurality of flutes 590 defines a flute opening 592 and a flute closure (not visible). The flute opening 592 forms an end-most portion of the fluid pathway 556 along the flutes to accommodate fluid flow into or out of the filter assembly 550. The flute closure obstructs fluid flow along the flute, thereby defining a portion of the fluid pathway 556 through the filter media 560. So, for example, a plurality of inlet flutes can define the flute opening 592 at the first flow face 570 and a flute closure is defined across the plurality of inlet flutes towards the second flow face 580. In some embodiments, the flute closure is adjacent to the second flow face 580. More particularly, the flute closure can abut the second flow face 580. The flute closure can be similar to flute closures discussed above.

In the current embodiment, the volume defined between an outer surface 566 of the first sheet of filter media 562 (FIG. 15A) and an outer surface 568 of the second sheet of filter media 564 (FIG. 15B) when the filter media is coiled (FIG. 15A) defines a fluid pathway 556 that is not necessarily characterized as being defined by a plurality of flutes.

An obstruction can be disposed within the coil and outside of the plurality of flutes 590 such that fluids passing through the first flow face 570 and second flow face 580 of the filter assembly 550 must first pass through the filter media 560. Additional obstructions can also be disposed in any other gaps in the filter media to prevent fluid flow there-through, such as around the outer perimeter of the filter assembly 550 and in a central opening of the filter assembly 550. An obstruction can be formed through depositing an adhesive, such as a glue bead at the relevant location.

Each of the plurality of flutes 590 defines a flute distance between the first flow face 570 and the second flow face 580. In the current embodiment, a first flute 594 of the plurality of flutes 590 defines a first flute distance D₁ between the first flow face 570 and the second flow face 580 and a second flute 596 of the plurality of flutes 590 defines a second flute distance D₂ between the first flow face 570 and the second flow face 580. In some examples, the first flute distance D₁ is less than the second flute distance D₂, as currently depicted. In some other examples, the first flute distance D₁ is greater than the second flute distance D₂. In certain embodiments, the first flute distance D₁ and the second flute distance D₂ differ by greater than 2 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by at least 5 mm, at least 8 mm or even at least 15 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by 3 mm to 570 mm, 560 mm to 570 mm, or 15 mm to 25 mm.

In some embodiments, a third flute 598 of the plurality of flutes 590 defines a third flute distance D₃ between the first flow face 570 and the second flow face 580. The third flute distance D₃ will generally differ from at least one of the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. In some embodiments the third flute distance D₃ differs from both the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. The third flute distance D₃ can differ from one or both the first flute distance D₁ and the second flute distance D₂ by similar ranges described above. In the current example, the third flute distance D₃ is greater than the first flute distance D₁ and the second flute distance D₂. In some other examples, the third flute distance D₃ is greater than one of the first flute distance D₁ and the second flute distance D₂, and less than the other of the first flute distance D₁ and the second flute distance D₂, as will be appreciated.

The differences in flute distances between the first flow face 570 of the filter assembly 550 and the second flow face 580 of the filter assembly 550 is also evidenced by the shapes of the flow faces relative to each other. In various embodiments, at least one of the first flow face 570 and the second flow face 580 is non-planar. In various embodiments, at least one of the first flow face 570 and the second flow face 580 is substantially planar. In examples consistent with this particular embodiment, the first flow face 570 is non-planar and the second flow face 580 is planar. Further, in this particular embodiment, the first flow face 570 has a stepped configuration where the first flow face 570 defines multiple planes 576. Each plane can be offset from other planes forming the first flow face 570 in the axial direction Z. The general shape of the first flow face 520 can be radially symmetrical relative to the Z-axis, although in some embodiments the general shape of the first flow face is asymmetrical to the Z-axis.

It will be appreciated that, in some alternative embodiments, the first flow face 570 can be planar and the second flow face 580 can be non-planar. In some embodiments at least one flute in the plurality of flutes 590 defines a flute opening that is non-planar.

In examples consistent with the current embodiment, an obstruction 599 is disposed adjacent to the fourth edge 567 of the second sheet of filter media 564 along the length of the second sheet of filter media 564. As the fourth edge 567 of the second sheet of filter media 564 is generally planar when the filter media 560 is in a coiled configuration, the obstruction 599 also is generally planar when the filter media 560 is in a coiled configuration.

Similar to the previous two examples, FIG. 16A depicts one example filter assembly 1800 consistent with the technology disclosed herein, where the filter assembly 1800 is coiled filter media 1810, and FIG. 16B depicts a facing view of the filter media 1810 in an uncoiled arrangement. The filter assembly 1800 is constructed of filter media 1810 defining a first flow face 1820, a second flow face 1830, and a plurality of flutes 1840 extending from the first flow face 1820 to the second flow face 1830. In the current example, the first flow face 1820 is defined on a first end 1802 of the filter assembly 1800 and the second flow face 1830 is defined on a second, opposite end 1804 of the filter assembly 1800. The first flow face 1820 has an axial flow face length L and the first flow face 1820 defines a taper for at least a portion of the axial flow face length L. In the current example, the taper of the first flow face 1820 increases for at least a portion of the axial flow face length L.

The filter media 1810 is a plurality of sheets of filter media, specifically a first sheet of filter media 1812 and a second sheet of filter media 1814. The second sheet of filter media 1814 is visible in FIG. 16B, which is a portion of the filter media 1810 in a planar, uncoiled arrangement. FIG. 16B is a facing view of the second sheet of filter media 1814. The second sheet of filter media 1814 is adjacent to the first sheet of filter media 1812. The first sheet of filter media 1812 and the second sheet of filter media 1814 mutually define the plurality of flutes 1840. The filter media 1810 can have a variety of configurations, some examples of which are described in association with FIGS. 6a-6d , and also described below.

The filter media 1810 defines a coiled configuration about a Z-axis. Accordingly, each of the first sheet of filter media 1812 and the second sheet of filter media 1814 defines a coiled configuration around the Z-axis. As such, the plurality of flutes 1840 are also in a coiled configuration about the Z-axis. In the current embodiment the plurality of flutes are parallel, but in some other embodiments the plurality of flutes are not parallel.

As visible in FIG. 16B, the filter media 1810 (particularly the first sheet of filter media 1812 and the second sheet of filter media 1814) are generally elongate, which enables the first sheet of filter media 1812 and the second sheet of filter media 1814 to be coiled about the Z-axis to form a filter assembly. In this example, the first sheet of filter media 1812 and the second sheet of filter media 1814 can be discontinuous. In such embodiments, the first sheet of filter media 1812 defines a first edge 1811 and a second edge 1813 (FIG. 16A) and the second sheet of filter media 1814 defines a third edge 1815 and a fourth edge 1817 (FIG. 16B). The first edge 1811 and the third edge 1815 mutually define the first flow face 1820 of the filter assembly 1800. The second edge 1813 and the fourth edge 1817 mutually define the second flow face 1830 of the filter assembly 1800. The first edge 1811 and third edge 1815 mutually and individually form a curved line, which has convex and concave portions. The second edge 1813 and the fourth edge 1817 mutually and individually form a straight line.

The filter media 1810 in examples consistent with the current embodiment has four edges: a first elongate edge 1805 (corresponding to the first edge 1811 and the third edge 1815), a second elongate edge 1807 (corresponding to the second edge 1813 and the fourth edge 1817), a first terminal edge 1808, and a second terminal edge 1809. The shape of the filter media 1810 is generally non-rectangular and non-trapezoidal at least based on the curve defined by the first elongate edge 1805.

The filter assembly 1800 is generally constructed to define a fluid pathway 1806 between the first flow face 1820 and the second flow face 1830 through the filter media 1810 such that the fluid is filtered by the filter media 1810. In particular, the plurality of flutes 1840 defines either inlet flutes, or outlet flutes, similar to as-described in FIG. 3.

Each of the plurality of flutes 1840 defines a flute opening 1842 and a flute closure (not visible). The flute opening 1842 forms an end-most portion of the fluid pathway 1806 along the flutes to accommodate fluid flow into or out of the filter assembly 1800. The flute closure obstructs fluid flow along the flute, thereby defining a portion of the fluid pathway 1806 through the filter media 1810. So, for example, a plurality of inlet flutes can define the flute opening 1842 at the first flow face 1820 and a flute closure is defined across the plurality of inlet flutes towards the second flow face 1830. In some embodiments, the flute closure is adjacent to the second flow face 1830. More particularly, the flute closure can abut the second flow face 1830. The flute closure can be similar to flute closures discussed above.

In the current embodiment, the volume defined between an outer surface 1816 of the first sheet of filter media 1812 (FIG. 16A) and an outer surface 1818 of the second sheet of filter media 1814 (FIG. 16B) when the filter media is coiled (FIG. 16A) defines a fluid pathway 1806 that is not necessarily characterized as being defined by a plurality of flutes.

An obstruction can be disposed within the coil and outside of the plurality of flutes 1840 such that fluids passing through the first flow face 1820 and second flow face 1830 of the filter assembly 1800 must first pass through the filter media 1810. Additional obstructions can also be disposed in any other gaps in the filter media to prevent fluid flow there-through, such as around the outer perimeter of the filter assembly 1800 and in a central opening of the filter assembly 1800. An obstruction can be formed through depositing an adhesive, such as a glue bead at the relevant location.

Each of the plurality of flutes 1840 defines a flute distance between the first flow face 1820 and the second flow face 1830. In the current embodiment, a first flute 1844 of the plurality of flutes 1840 defines a first flute distance D₁ between the first flow face 1820 and the second flow face 1830 and a second flute 1846 of the plurality of flutes 1840 defines a second flute distance D₂ between the first flow face 1820 and the second flow face 1830. In some examples, the first flute distance D₁ is less than the second flute distance D₂, as currently depicted. In some other examples, the first flute distance D₁ is greater than the second flute distance D₂. In certain embodiments, the first flute distance D₁ and the second flute distance D₂ differ by greater than 2 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by at least 10 mm, at least 8 mm or even at least 15 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by 3 mm to 1020 mm, 1010 mm to 1020 mm, or 15 mm to 25 mm.

In some embodiments, a third flute 1848 of the plurality of flutes 1840 defines a third flute distance D₃ between the first flow face 1820 and the second flow face 1830. The third flute distance D₃ will generally differ from at least one of the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. In some embodiments the third flute distance D₃ differs from both the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. The third flute distance D₃ can differ from one or both the first flute distance D₁ and the second flute distance D₂ by similar ranges described above. In the current example, the third flute distance D₃ is greater than the first flute distance D₁ and the second flute distance D₂. In some other examples, the third flute distance D₃ is greater than one of the first flute distance D₁ and the second flute distance D₂, and less than the other of the first flute distance D₁ and the second flute distance D₂, as will be appreciated.

The differences in flute distances between the first flow face 1820 of the filter assembly 1800 and the second flow face 1830 of the filter assembly 1800 is also evidenced by the shapes of the flow faces relative to each other. In various embodiments, at least one of the first flow face 1820 and the second flow face 1830 is non-planar. In various embodiments, at least one of the first flow face 1820 and the second flow face 1830 is substantially planar. In examples consistent with this particular embodiment, the first flow face 1820 is non-planar and the second flow face 1830 is planar. Further, in this particular embodiment, the first flow face 1820 is configured such that it protrudes outward from the filter assembly in the axial direction Z. The general shape of the first flow face 1820 can be considered radially symmetrical relative to the Z-axis.

It will be appreciated that, in some alternative embodiments, the first flow face 1820 can be planar and the second flow face 1830 can be non-planar. In some embodiments at least one flute in the plurality of flutes 1840 defines a flute opening that is non-planar.

In examples consistent with the current embodiment, an obstruction 1849 is disposed adjacent to the fourth edge 1817 of the second sheet of filter media 1814 along the length of the second sheet of filter media 1814. As the fourth edge 1817 of the second sheet of filter media 1814 is generally planar when the filter media 1810 is in a coiled configuration, the obstruction 1849 also is generally planar when the filter media 1810 is in a coiled configuration.

FIG. 17A depicts yet another example filter assembly 1100 consistent with the technology disclosed herein, where the filter assembly 1100 is coiled filter media 1110, and FIG. 17B depicts a facing view of the filter media 1110 in an uncoiled arrangement. The filter assembly 1100 is constructed of filter media 1110 defining a first flow face 1120, a second flow face 1130, and a plurality of flutes 1140 extending from the first flow face 1120 to the second flow face 1130. In the current example, the first flow face 1120 is defined on a first end 1102 of the filter assembly 1100 and the second flow face 1130 is defined on a second, opposite end 1104 of the filter assembly 1100. The first flow face 1110 has an axial flow face length L. In this example, the first flow face 1120 does not define a taper along at least a portion of the axial flow face length L.

The filter media 1110 is a plurality of sheets of filter media, specifically a first sheet of filter media 1112 and a second sheet of filter media 1114. The second sheet of filter media 1114 is visible in FIG. 17B, which is a portion of the filter media 1110 in a planar arrangement. FIG. 17B is a facing view of the second sheet of filter media 1114. The second sheet of filter media 1114 is adjacent to the first sheet of filter media 1112. The first sheet of filter media 1112 and the second sheet of filter media 1114 mutually define the plurality of flutes 1140. The filter media 1110 can have a variety of configurations, some examples of which are described in association with FIGS. 6a-6d , and also described below.

It is noted that the totality of the flutes that would be defined in an actual implementation of this design have been omitted from FIG. 17A to simplify the drawing and provide clarity regarding the relatively complex shape of the first flow face 1120.

The filter media 1110 defines a coiled configuration about a Z-axis. Accordingly, each of the first sheet of filter media 1112 and the second sheet of filter media 1114 defines a coiled configuration around the Z-axis. As such, the plurality of flutes 1140 are also in a coiled configuration about the Z-axis. In the current embodiment the plurality of flutes are parallel, but in some other embodiments the plurality of flutes are not parallel.

As visible in FIG. 17B, the filter media 1110 (particularly the first sheet of filter media 1112 and the second sheet of filter media 1114) are generally elongate, which enables the first sheet of filter media 1112 and the second sheet of filter media 1114 to be coiled about the Z-axis to form a filter assembly. In this example, the first sheet of filter media 1112 and the second sheet of filter media 1114 are continuous or discontinuous. In embodiments where the sheets are discontinuous, the first sheet of filter media 1112 defines a first edge 1111 and a second edge 1113 (FIG. 17A), and the second sheet of filter media 1114 defines a third edge 1115 and a fourth edge 1117 (FIG. 17B). The first edge 1111 and the third edge 1115 mutually define the first flow face 1120 of the filter assembly 1100. The second edge 1113 and the fourth edge 1117 mutually define the second flow face 1130 of the filter assembly 1100. The first edge 1111 and third edge 1115 each individually forms a sine wave pattern having a constant frequency across the length of the filter media 1110. The second edge 1113 and the fourth edge 1117 each individually forms a straight line.

The filter media 1110 in examples consistent with the current embodiment has four edges: a first elongate edge 1105 (corresponding to the first edge 1111 and the third edge 1115), a second elongate edge 1107 (corresponding to the second edge 1113 and the fourth edge 1117), a first terminal edge 1108, and a second terminal edge 1109. The shape of the filter media 1110 is generally non-rectangular and non-trapezoidal at least based on the wave pattern defined by the first elongate edge, which defines a plurality of convex and concave portions.

The filter assembly 1100 is generally constructed to define a fluid pathway 1106 between the first flow face 1120 and the second flow face 1130 through the filter media 1110 such that the fluid is filtered by the filter media 1110. In particular, the plurality of flutes 1140 defines either inlet flutes, or outlet flutes, similar to as-described in FIG. 3.

Each of the plurality of flutes 1140 defines a flute opening 1142 and a flute closure (not visible). The flute opening 1142 forms an end-most portion of the fluid pathway 1106 along the flutes to accommodate fluid flow into or out of the filter assembly 1100. The flute closure obstructs fluid flow along the flute, thereby defining a portion of the fluid pathway 1106 through the filter media 1110. So, for example, a plurality of inlet flutes can define the flute opening 1142 at the first flow face 1120 and a flute closure is defined across the plurality of inlet flutes towards the second flow face 1130. In some embodiments, the flute closure is adjacent to the second flow face 1130. More particularly, the flute closure can abut the second flow face 1130. The flute closure can be similar to flute closures discussed above.

In the current embodiment, the volume defined between an outer surface 1116 of the first sheet of filter media 1112 (FIG. 17A) and an outer surface 1118 of the second sheet of filter media 1114 (FIG. 17B) when the filter media is coiled (FIG. 17A) defines a fluid pathway 1106 that is not necessarily characterized as being defined by a plurality of flutes.

An obstruction can be disposed within the coil and outside of the plurality of flutes 1140 such that fluids passing through the first flow face 1120 and second flow face 1130 of the filter assembly 1100 must first pass through the filter media 1110. Additional obstructions can also be disposed in any other gaps in the filter media to prevent fluid flow there-through, such as around the outer perimeter of the filter assembly 1100 and in a central opening of the filter assembly 1100. An obstruction can be formed through depositing an adhesive, such as a glue bead at the relevant location.

Each of the plurality of flutes 1140 defines a flute distance between the first flow face 1120 and the second flow face 1130. In the current embodiment, a first flute 1144 of the plurality of flutes 1140 defines a first flute distance D₁ between the first flow face 1120 and the second flow face 1130 and a second flute 1146 of the plurality of flutes 1140 defines a second flute distance D₂ between the first flow face 1120 and the second flow face 1130. In some examples, the first flute distance D₁ is less than the second flute distance D₂, as currently depicted. In some other examples, the first flute distance D₁ is greater than the second flute distance D₂. In certain embodiments, the first flute distance D₁ and the second flute distance D₂ differ by greater than 2 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by at least 5 mm, at least 8 mm or even at least 15 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by 3 mm to 20 mm, 10 mm to 20 mm, or 15 mm to 25 mm.

In some embodiments, a third flute 1148 of the plurality of flutes 1140 defines a third flute distance D₃ between the first flow face 1120 and the second flow face 1130. The third flute distance D₃ will generally differ from at least one of the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. In some embodiments the third flute distance D₃ differs from both the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. The third flute distance D₃ can differ from one or both the first flute distance D₁ and the second flute distance D₂ by similar ranges described above. In the current example, the third flute distance D₃ is greater than the first flute distance D₁ and the second flute distance D₂. In some other examples, the third flute distance D₃ is greater than one of the first flute distance D₁ and the second flute distance D₂, and less than the other of the first flute distance D₁ and the second flute distance D₂, as will be appreciated.

The differences in flute distances between the first flow face 1120 of the filter assembly 1100 and the second flow face 1130 of the filter assembly 1100 is also evidenced by the shapes of the flow faces relative to each other. In various embodiments, at least one of the first flow face 1120 and the second flow face 1130 is non-planar. In various embodiments, at least one of the first flow face 1120 and the second flow face 1130 is substantially planar. In examples consistent with this particular embodiment, the first flow face 1120 is non-planar and the second flow face 1130 is planar. Further, in this particular embodiment, the first flow face 1120 is configured such that the first elongate edge of the filter media 1110 undulates circumferentially about the Z-axis.

It will be appreciated that, in some alternative embodiments, the first flow face 1120 can be planar and the second flow face 1130 can be non-planar. In some embodiments at least one flute in the plurality of flutes 1140 defines a flute opening that is non-planar.

In examples consistent with the current embodiment, an obstruction 1149 is disposed adjacent to the fourth edge 1117 of the second sheet of filter media 1114 along the length of the second sheet of filter media 1114. As the fourth edge 1117 of the second sheet of filter media 1114 is generally planar when the filter media 1110 is in a coiled configuration, the obstruction 1149 also is generally planar when the filter media 1110 is in a coiled configuration.

FIG. 18 depicts a side cut-away view of yet another example filter assembly 1200 consistent with the technology disclosed herein. The filter assembly 1200 is constructed of filter media 1210 having a first elongate edge 1212 defining a first flow face 1220, a second elongate edge 1214 defining a second flow face 1230, and a plurality of flutes 1240 extending from the first flow face 1220 to the second flow face 1230. In the current example, the first flow face 1220 is defined on a first end 1202 of the filter assembly 1200 and the second flow face 1230 is defined on a second, opposite end 1204 of the filter assembly 1200. The first flow face 1220 has a first axial flow face length L₁ and the second flow face 1230 has a second axial flow face length L₂. Each of the first flow face 1220 and the second flow face 1230 defines a taper along the respective axial flow face length.

Similar to other embodiments described herein, the filter assembly 1200 is generally constructed to define a fluid pathway 1218 between the first flow face 1220 and the second flow face 1230 through the filter media 1210 such that the fluid is filtered by the filter media 1210. In this example, each of the plurality of flutes 1240 defines a flute opening and a flute closure, as described with reference to previous figures. Also similar to some other embodiments, the filter assembly 1200 is constructed of filter media 1210 that is in a coiled configuration about a Z-axis. The first sheet of filter media 1250 and the second sheet of filter media 1260 mutually define the plurality of flutes 1240. The filter media 1210 has a first sheet of filter media 1250 that is fluted and a second sheet of filter media 1260 that is a facing sheet adjacent to the first sheet of filter media 1250. The filter assembly 1200 of FIG. 18 can be constructed from variety of configurations of filter media 1210, examples of which are described in association with FIGS. 6a-6d , and also as-described below.

The first sheet of filter media 1250 and the second sheet of filter media 1260 are generally elongate. In this example, the first sheet of filter media 1250 and the second sheet of filter media 1260 are discontinuous. The first sheet of filter media 1250 defines a first edge 1253 and the second sheet of filter media 1260 defines a second edge 1263. The first edge 1253 and the second edge 1263 are configured to mutually define the first flow face 1220, and therefore the first elongate edge 1212, of the filter assembly 1200. The first sheet of filter media 1250 defines a third edge 1255 and the second sheet of filter media 1260 defines a fourth edge 1265. The third edge 1255 and the fourth edge 1265 are configured to mutually define the second flow face 1230, and therefore the second elongate edge 1214, of the filter assembly 1200.

Each of the first sheet of filter media 1250 and the second sheet of filter media 1260 are arranged to define a coiled configuration about the Z-axis. As such, the plurality of flutes 1240 are also in a coiled configuration about the Z-axis. In this example, the plurality of flutes 1240 are generally parallel.

Each of the plurality of flutes 1240 defines a flute distance between the first flow face 1220 and the second flow face 1230. In the current embodiment, a first flute 1244 of the plurality of flutes 1240 defines a first flute distance D₁ between the first flow face 1220 and the second flow face 1230 and a second flute 1246 of the plurality of flutes 1240 defines a second flute distance D₂ between the first flow face 1220 and the second flow face 1230. In the current embodiment the first flute distance D₁ is less than the second flute distance D₂, but in other embodiments the first flute distance D₁ is greater than the second flute distance D₂. In a variety of embodiments, the first flute distance D₁ and the second flute distance D₂ differ by greater than 2 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by at least 5 mm, at least 8 mm or even at least 15 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by 3 mm to 20 mm, 10 mm to 20 mm, or 15 mm to 25 mm.

In some embodiments, a third flute 1248 of the plurality of flutes 1240 defines a third flute distance D₃ between the first flow face 1220 and the second flow face 1230. In the current embodiment the third flute distance D₃ is greater than the first flute distance D₁ and the second flute distance D₂, but flute distances can have other relative relationships, as has been described above. The third flute distance D₃ will generally differ from at least one of the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. In some embodiments the third flute distance D₃ differs from both the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. The third flute distance D₃ can differ from one or both the first flute distance D₁ and the second flute distance D₂ by similar ranges described above.

In examples consistent with this particular embodiment, the first flow face 1220 is non-planar and the second flow face 1230 is non-planar. One or both of the first flow face and the second flow face can be cut to be a three-dimensional surface. In the current example, at least one of the first flow face 1220 and the second flow face 1230 is recessed and, as such, defines a void that projects inward relative to the filter assembly 1200. In the current example, the first flow face 1220 and the second flow face 1230 each define a depression and are each recessed. In some other embodiments, one of the first flow face 1220 and the second flow face 1230 is recessed relative to the filter assembly, and the other of the first flow face 1220 and the second flow face 1230 is planar or protrudes. In the current example, the general shape of the first flow face 1220 and the second flow face 1230 are symmetrical relative to the Z-axis. In some other embodiments, the first flow face 1220 and the second flow face 1230 are asymmetrical relative to the Z-axis. In some embodiments the first flow face 1220 and the second flow face 1230 have similar shapes, and in other embodiments the first flow face 1220 and the second flow face 1230 have dissimilar shapes.

FIG. 19 depicts a side cut-away view of yet another example filter assembly 1300 consistent with the technology disclosed herein. The filter assembly 1300 is constructed of filter media 1310 having a first elongate edge 1312 defining a first flow face 1320, a second elongate edge 1314 defining a second flow face 1330, and a plurality of flutes 1340 extending from the first flow face 1320 to the second flow face 1330. In the current example, the first flow face 1320 is defined on a first end 1302 of the filter assembly 1300 and the second flow face 1330 is defined on a second, opposite end 1304 of the filter assembly 1300. The first flow face 1320 has a first axial flow face length L₁ and the second flow face 1330 has a second axial flow face length L₂. Each of the first flow face 1320 and the second flow face 1330 defines a taper along the respective axial flow face length.

Similar to other embodiments described herein, the filter assembly 1300 is generally constructed to define a fluid pathway 1318 between the first flow face 1320 and the second flow face 1330 through the filter media 1310 such that the fluid is filtered by the filter media 1310. As such, each of the plurality of flutes 1340 defines a flute opening and a flute closure, as described with reference to previous figures. Also similar to some other embodiments, the filter assembly 1300 is constructed of filter media 1310 that is in a coiled configuration about a Z-axis. The filter media 1310 has a first sheet of filter media that is fluted and a second sheet of filter media adjacent to the first sheet of filter media (not currently distinguishable from this view). The first sheet of filter media and the second sheet of filter media mutually define the plurality of flutes. The filter assembly 1300 of FIG. 19 can be constructed from variety of alternate configurations of filter media 1310, examples of which are described in association with FIGS. 6a-6d , and also as described below.

Each of the first sheet of filter media and the second sheet of filter media are arranged to define a coiled configuration about the Z-axis. As such, the plurality of flutes are also in a coiled configuration about the Z-axis. In this example, the plurality of flutes 1340 are generally parallel.

Each of the plurality of flutes 1340 defines a flute distance between the first flow face 1320 and the second flow face 1330. In the current embodiment, a first flute 1344 of the plurality of flutes 1340 defines a first flute distance D₁ between the first flow face 1320 and the second flow face 1330 and a second flute 1346 of the plurality of flutes 1340 defines a second flute distance D₂ between the first flow face 1320 and the second flow face 1330. In the current embodiment the first flute distance D₁ is less than the second flute distance D₂, but in other embodiments the first flute distance D₁ is greater than the second flute distance D₂. In a variety of embodiments, the first flute distance D₁ and the second flute distance D₂ differ by greater than 13 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by at least 5 mm, at least 8 mm or even at least 15 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by 3 mm to 20 mm, 10 mm to 20 mm, or 15 mm to 25 mm.

In some embodiments, a third flute 1348 of the plurality of flutes 1340 defines a third flute distance D₃ between the first flow face 1320 and the second flow face 1330. In the current embodiment the third flute distance D₃ is greater than the first flute distance D₁ and the second flute distance D₂, but flute distances can have other relative relationships, as has been described above. The third flute distance D₃ will generally differ from at least one of the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. In some embodiments the third flute distance D₃ differs from both the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. The third flute distance D₃ can differ from one or both the first flute distance D₁ and the second flute distance D₂ by similar ranges described above.

In various embodiments, at least one of the first flow face 1320 and the second flow face 1330 is planar. In examples consistent with this particular embodiment, the first flow face 1320 is planar and the second flow face 1330 is planar, and the first flow face 1320 is non-parallel and non-perpendicular to the second flow face 1330. Unlike the example of FIG. 5, here each of the flow faces are not perpendicular to the flutes.

FIG. 20 depicts a side cut-away view of yet another example filter assembly 1400 consistent with the technology disclosed herein. The filter assembly 1400 is constructed of filter media 1410 having a first elongate edge 1412 defining a first flow face 1420, a second elongate edge 1414 defining a second flow face 1430, and a plurality of flutes 1440 extending from the first flow face 1420 to the second flow face 1430. In the current example, the first flow face 1420 is defined on a first end 1402 of the filter assembly 1400 and the second flow face 1430 is defined on a second, opposite end 1404 of the filter assembly 1400. The first flow face 1420 has a first axial flow face length L₁ and the second flow face 1430 has a second axial flow face length L₂. Each of the first flow face 1420 and the second flow face 1430 defines a taper along its respective axial flow face length.

Similar to other embodiments described herein, the filter assembly 1400 is generally constructed to define a fluid pathway 1418 between the first flow face 1420 and the second flow face 1430 through the filter media 1410 such that the fluid is filtered by the filter media 1410. As such, each of the plurality of flutes 1440 defines a flute opening and a flute closure, as described with reference to previous figures. Also similar to some other embodiments, the filter assembly 1400 is constructed of filter media 1410 that is in a coiled configuration about a Z-axis. The filter media 1410 has a first sheet of filter media that is fluted and a second sheet of filter media adjacent to the first sheet of filter media (not discernable in this view). The first sheet of filter media and the second sheet of filter media can be consistent with examples described in association with FIGS. 6a-6d , and also examples as-described below.

Each of the first sheet of filter media and the second sheet of filter media are arranged to define a coiled configuration about the Z-axis. As such, the plurality of flutes 1440 are also in a coiled configuration about the Z-axis. In this example, the plurality of flutes 1440 are generally parallel.

Each of the plurality of flutes 1440 defines a flute distance between the first flow face 1420 and the second flow face 1430. In the current embodiment, a first flute 1444 of the plurality of flutes 1440 defines a first flute distance D₁ between the first flow face 1420 and the second flow face 1430 and a second flute 1446 of the plurality of flutes 1440 defines a second flute distance D₂ between the first flow face 1420 and the second flow face 1430. In the current embodiment the first flute distance D₁ is less than the second flute distance D₂, but in other embodiments the first flute distance D₁ is greater than the second flute distance D₂. In a variety of embodiments, the first flute distance D₁ and the second flute distance D₂ differ by greater than 2 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by at least 5 mm, at least 8 mm or even at least 15 mm. In some embodiments, the first flute distance D₁ differs from the second flute distance D₂ by 3 mm to 20 mm, 10 mm to 20 mm, or 15 mm to 25 mm.

In some embodiments, a third flute 1448 of the plurality of flutes 1440 defines a third flute distance D₃ between the first flow face 1420 and the second flow face 1430. In the current embodiment the third flute distance D₃ is greater than the first flute distance D₁ and the second flute distance D₂, but flute distances can have other relative relationships, as has been described above. The third flute distance D₃ will generally differ from at least one of the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. In some embodiments the third flute distance D₃ differs from both the first flute distance D₁ and the second flute distance D₂ by greater than 2 mm. The third flute distance D₃ can differ from one or both the first flute distance D₁ and the second flute distance D₂ by similar ranges described above.

In examples consistent with this particular embodiment, the first flow face 1420 is non-planar and the second flow face 1430 is non-planar. One or both of the first flow face and the second flow face can be cut to be a three-dimensional surface. In the current example, at least one of the first flow face 1420 and the second flow face 1430 protrudes relative to the filter assembly 1400. In the current example, the first flow face 1420 and the second flow face 1430 each protrude axially outward from the filter assembly 1400 (in the Z-direction). In some alternate embodiments, at least one of the first flow face 1420 and the second flow face 1430 protrudes outward and the other of the first flow face 1420 and the second flow face 1430 is recessed or is planar.

Additional Media Configurations

The filter assemblies described herein can be constructed of filter media having a variety of different configurations, including those already depicted herein. Various embodiments, including in any of the example filter assemblies disclosed herein, can incorporate filter media constructed of a fluted sheet and a facing sheet adjacent to the fluted sheet, where a plurality of flutes is defined that extend between the fluted sheet and facing sheet. In some of those embodiments, the fluted sheet defines a plurality of protrusions that contact the facing sheet. Example filter medias are described, for example, in U.S. Pat. No. 9,623,362, which is incorporated by reference herein.

Also, in some of those embodiments, the fluted sheet defines a ridge along at least a portion of the length of a portion of the flutes, where a ridge is a line of intersection between differently-sloped portions of media forming the particular flute. Also, in some of those embodiments, at least a portion of the flutes can define flute peaks that are sharp, meaning the flute peak is not curved. Also, in some of those embodiments, at least a portion of the flutes can be tapered from a first flow face of the media assembly to the second flow face of the media assembly. The above and other flute configuration are certainly contemplated, such as disclosed in U.S. Pat. Nos. 7,959,702 and 8,545,589, which are each incorporated by reference herein. In some embodiments, flutes do not extend from a first flow face to a second flow face of the filter media, such as where a portion of the flutes taper to a point between the first flow face and second flow face of the filter media.

Filter assemblies constructed of fluted media consistent with the technology disclosed herein can incorporate different types of filter media arranged in parallel or in a series, where “different types of filter media” is used to mean that the filter media is constructed of different materials, or has flutes that exhibit differences in flute shape, flute size, flute height, flute width, flute length, cross-flute area, and/or filter media. Such configurations are described in PCT Pub. No. WO 2008/111923 and U.S. Pat. App. No. 62/683,542, which are incorporated herein by reference.

In some embodiments, where the filter media is constructed of a fluted sheet and a facing sheet that mutually defines a plurality of flutes, the plurality of flutes has at least a first group of flutes and a second group of flutes, where the first and second group of flutes exhibit differences in flute shape, flute size, flute height, flute width, flute length, cross-flute area, and/or filter media.

FIG. 21 depicts a cross-sectional view of an example filter media 1500 consistent with various embodiments. A first sheet of filter media 1502 and a second sheet of filter media 1504 mutually define a plurality of flutes 1506. The filter assembly 1500 has two types of flutes: first flutes 1510, and second flutes 1520. The first flutes 1510 and second flutes 1520 are arranged in parallel flow. The filter media 1500 can be used to form coiled filter assemblies (as has been described), or the filter media 1500 can be stacked with similar or different filter media to form panel filter assemblies consistent with embodiments herein. In example constructions having two types of flutes, as currently depicted, the first and second flutes can be selected such that the first plurality of flutes comprises 20 to 50 percent of the volume of the filter assembly, such as 20, 30, 40, or 50 percent the volume of filter assembly; the second plurality of flutes comprises 20 to 50 percent the volume of the pack, such as 20, 30, 40 or 50 percent of the volume of filter assembly.

In an example construction having two types of flutes, the first and second flutes can be selected such that the first plurality of flutes comprises 20 to 50 percent of the media surface area of the filter assembly, such as 20, 30, 40, or 50 percent of the media surface area of the filter assembly; and the second plurality of flutes comprises 20 to 50 percent of the media surface area of the filter assembly, such as 20, 30, 40 or 50 percent of the media surface area of the filter assembly.

In an example construction having two types of flutes, the first and second flutes can be selected such that the first plurality of flutes comprises 20 to 50 percent of the inlet face of the filter assembly, such as 20, 30, 40, or 50 percent of the inlet face of the filter assembly; and the second plurality of flutes comprises 20 to 50 percent of the inlet face of the filter assembly, such as 20, 30, 40 or 50 percent of the inlet face of the filter assembly.

While FIG. 21 depicts two different types of flutes, other embodiments can have additional different types of flutes incorporated in the filter media.

Filter assemblies having a stacked configuration as described herein can be constructed of multiple different types of filter media in the stack. FIG. 22 is a facing schematic view of an example filter assembly 1600, showing a stacked configuration with two types of filter media. The two types of filter media are first media 1610 and a second media 1620. The filter media are arranged in parallel with respect to fluid flow. The media is shown in a stacked configuration with the two types of filter media being segregated by media type rather than intermixed. In this example embodiment the ratio of filter media 1610 to 820 to 830 is approximately 4:3, based upon filter assembly inlet (or outlet) area.

In some implementations the first media (having a first plurality of flutes) defines from 10 to 90 percent of the inlet face of the media assembly, such as 10, 20, 30, 40, 50, 60, 70, 80 or 90 percent of the inlet face of the filter assembly; and the second filter assembly (having a second plurality of flutes) defines from 90 to 10 percent of the inlet face of the media assembly, such as 90, 80, 70, 60, 50, 40, 30, 20 or 10 percent of the inlet face of the media assembly. Alternatively, the first plurality of flutes comprises from 20 to 40 percent of the inlet face of the media assembly, and the second plurality of flutes comprises from 60 to 80 percent of the inlet face of the media assembly. In other implementations the first plurality of flutes comprises from 40 to 60 percent of the inlet face of the media assembly, and the second plurality of flutes comprises from 60 to 40 percent of the inlet face of the media assembly. In yet another implementation the first plurality of flutes comprises from 60 to 90 percent of the inlet face of the media assembly, and the second plurality of flutes comprises from 40 to 10 percent of the inlet face of the media assembly.

Media assemblies having a coiled media arrangement consistent with the present disclosure can also be constructed of multiple types of filter media arranged in a series. FIG. 23 is a schematic cross-sectional view of an example filter assembly 1700, showing a wound configuration with two types of filter media 1710 and 1720. The media is coiled with the first media 1710 on the inside and the second media 1720 on the outside. The first and second medias 1710, 1720 are spliced together. While the flutes are not currently depicted, it should be understood that each of the first and second media is generally fluted media. The first 1710 and second 1720 medias can have ratios and parameters consistent with that described above with reference to FIG. 22.

FIG. 24 is a cross-sectional view of a two-stage separator system 2000 consistent with FIG. 1. Unlike FIG. 2, the current cross section is taken through the filter assembly as well as the separator housing, so that an alternate filter assembly configuration is visible. The separator system 2000 has a housing 2010 that houses a filter assembly 2050 disposed therein. The filter assembly 2050 can be generally consistent with filter assemblies described herein above.

The housing 2010 extends between a first end 2012 and a second end 2014. The housing 2010 defines an interior volume 2016. In various embodiments the housing 2010 extends in an axial direction defined by a central axis z. The housing 2010 defines a housing inlet 2020, a separator outlet 2030 towards the second end 2014, and a filtration outlet 2040 on the first end 2012. In this example, the housing inlet 2020 is defined towards the first end 2012. A filter assembly 2050 is positioned in the interior volume 2016. The housing 2010 is configured to receive unfiltered fluid, such as air, through the housing inlet 2020, allow expulsion of separated particulates through the separator outlet 2030, and allow filtered air to exit through filtration outlet 2040. This functionality similar to the description above with respect to FIGS. 1 and 2.

The housing 2010 has a main portion 2060 and an access cover 2070 that are detachably coupled. The main portion 2060 can define the first end 2012 of the housing 2010 and the access cover 2070 can define the second end 2014 of the housing 2010. The main portion 2060 and the access cover 2070 are detachably coupled as described above with reference to FIGS. 1 and 2. The access cover 2070 encloses the second end 2062 of the main portion 2060 of the housing 2010.

The specific configurations of the housing inlet 2020, separator outlet 2030, and filtration outlet 2040 can be similar to that described above with reference to FIGS. 1 and 2.

A filter assembly 2050 is disposed in the housing 2010, that is generally configured to filter air within the housing 2010. The filter assembly 2050 has an inlet flow face 2052, an outlet flow face 2054, and filter media 2056 extending in the axial direction between the inlet flow face 2052 and the outlet flow face 2054. While not visible in the current view, the filter media 2056 defines a plurality of flutes extending in the axial direction. The flutes can extend between the inlet flow face 2052 and the outlet flow face 2054 in the axial direction. The filter assembly 2050 is similar to the filter assembly depicted and discussed with respect to FIG. 18, in that each flow face 2052, 2054 has an axial length L₁, L₂, respectively. In particular, the inlet flow face 2052 and the outlet flow face 2054 is recessed and extends inward relative to the filter assembly 2050.

The filter assembly 2050 is coupled to the housing 2010 about the filtration outlet 2040 such that the outlet flow face 2054 is in fluid communication with the filtration outlet 2040. In various embodiments, the filter media 2056 surrounding the outlet flow face 2054 is coupled to the housing 2010 about the filtration outlet 2040. In the current example, the filter assembly 2050 has a potting feature 2026 that is a radial potting sleeve configured to receive a first end of the filter media 2056. The first end 2051 of the filter assembly 2050 can be coupled to the housing 2010 using adhesives, gaskets, compression fits, and/or through additional or alternative structures.

The filter assembly 2050 has an outer radial barrier surface 2058 between the inlet flow face 2052 and the outlet flow face 2054. In some embodiments, the outer radial barrier surface 2058 can be configured to guide airflow tangentially about the filter assembly 2050. The outer radial barrier surface 2058 can have a configuration consistent with the description above with respect to FIG. 2. The outer radial barrier surface 2058 has a length L_(surface) extending in the axial direction, which is greater than or equal to an axial distance D from the filtration outlet 2040 to a distal end of the housing inlet 2020. In some embodiments, the outer radial barrier surface 2058 extends axially from the filtration outlet 2040 beyond the housing inlet 2020. Such a configuration encourages spiraling airflow about the filter assembly 2050 towards the second end 2014 of the housing 2010.

The inlet flow face 2052 of the filter assembly 2050 has a flow face length L₁ in the axial direction z. Unlike the example of FIG. 2, here the inlet flow face 2052 defines a taper for at least a portion of the axial flow face length L_(inlet) from the second end 2014 towards the first end 2012 of the housing 2010. In some embodiments where the inlet flow face 2052 defines a taper for at least a portion of the axial flow face length L_(inlet), the taper increases for at least a portion of the axial flow face length L_(inlet) from the second end 2014 towards the first end 2012. The taper of the inlet flow face 2052 continuously changes along the axial flow face length L_(inlet) from the first end 2012 towards the second end 2014. Indeed, in the current example, the taper of the inlet flow face 2052 continuously increases along the axial flow face length L_(inlet) from the second end 2014 towards the first end 2012.

A radial distance R_(1,2) is generally defined between the inlet flow face 2052 and the housing 2010. In various embodiments, the radial distance R_(1,2) increases for at least a portion of the axial flow face length L_(inlet) from the second end 2014 towards the first end 2012 of the housing 2010, as demonstrated by a first radial distance R₁ and a second radial distance R₂. Similar to the discussion above with respect to FIG. 2, while the housing 2010 is not shown as tapering here, in some examples the housing can define a taper along at least a portion of the axial length of the housing 2010.

In the embodiment depicted, the filter media 2056 is at least a first sheet of filter media and a second sheet of filter media in a coiled configuration about the z-axis, similar to the filter assembly described above with respect to FIG. 18.

Description of Exemplary Embodiments of a Two-Stage Separator System of the Current Technology

Embodiment 1. A two-stage separator system comprising:

a housing extending between a first end and a second end, the housing defining a housing inlet, a separator outlet towards the second end, and a filtration outlet on the first end; and a filter assembly having a first sheet of filter media coupled to a second sheet of filter media mutually defining a plurality of flutes extending in an axial direction, wherein the filter assembly defines an inlet flow face and an outlet flow face, wherein the filter assembly is disposed in the housing and coupled to the housing about the filtration outlet such that the outlet flow face is in fluid communication with the filtration outlet, and wherein the inlet flow face has an axial flow face length.

Embodiment 2. The system of any one of claims 1 and 3-17, wherein a radial distance is defined between the inlet flow face and the housing, wherein the radial distance increases for at least a portion of the axial flow face length from the first end towards the second end.

Embodiment 3. The system of any one of embodiments 1-2 and 4-17, wherein the filter assembly has an outer radial barrier surface extending axially from the filtration outlet beyond the housing inlet.

Embodiment 4. The system of any one of embodiments 1-3 and 5-17, wherein the filter assembly has an outer radial barrier surface having an axial length from the outlet flow face towards the inlet flow face that is greater than or equal to an axial distance from the filtration outlet to a distal end of the housing inlet.

Embodiment 5. The system of any one of embodiments 1-4 and 6-17, wherein the housing inlet defines an airflow pathway that is tangential to an outer radial barrier surface of the filter assembly.

Embodiment 6. The system of any one of embodiments 1-5 and 7-17, wherein at least a portion of the outer radial barrier surface is defined by the first sheet of filter media.

Embodiment 7. The system of any one of embodiments 1-6 and 8-17, wherein the inlet flow face defines a taper for at least a portion of the axial flow face length from the first end towards the second end.

Embodiment 8. The system of any one of embodiments 1-7 and 9-17, wherein the taper increases for at least a portion of the axial flow face length from the first end towards the second end.

Embodiment 9. The system of any one of embodiments 1-8 and 10-17, wherein the taper continuously changes along the axial flow face length from the first end towards the second end.

Embodiment 10. The system of any one of embodiments 1-9 and 11-17, wherein the taper continuously increases along the axial flow face length from the first end towards the second end.

Embodiment 11. The system of any one of embodiments 1-10 and 12-17, wherein the first sheet of filter media is a facing sheet and the second sheet of filter media is a fluted sheet.

Embodiment 12. The system of any one of embodiments 1-11 and 13-17, wherein the first sheet of filter media and the second sheet of filter media define a coiled configuration about a z-axis extending in the axial direction.

Embodiment 13. The system of any one of embodiments 1-12 and 14-17, further comprising:

a rod extending centrally through the filter assembly, the rod having a proximal end positioned towards the outlet flow face and a distal end positioned towards the inlet flow face; and a rod receptacle defined by the second end of the housing, wherein the rod receptacle is configured to receive a distal end of the rod.

Embodiment 14. The system of any one of embodiments 1-13 and 15-17, wherein the distal end of the rod defines a handle.

Embodiment 15. The system of any one of embodiments 1-14 and 16-17, wherein the filter assembly has a circular cross-section.

Embodiment 16. The system of any one of embodiments 1-15 and 17, wherein the filter assembly comprises: a plurality of first sheets of filter media and a plurality of second sheets of filter media in an alternating, stacked configuration; and a radial sleeve disposed about the stacked first sheets of filter media and second sheets of filter media.

Embodiment 17. The system of any one of embodiments 1-16, wherein the housing inlet is defined towards the first end of the housing.

Description of Exemplary Filter Assembly Embodiments for Use in a Two-Stage Separator System of the Current Technology

Any of the following exemplary filter assemblies can be incorporated in a two-stage separator system as described herein:

Embodiment 1. A filter assembly comprising:

a first sheet of filter media and a second sheet of filter media mutually defining a first plurality of flutes, a first flow face on a first end of the filter assembly, and a second flow face on an opposite, second end of the filter assembly, wherein each of the first plurality of flutes defines a distance from the first flow face to the second flow face and each of the first plurality of flutes defines a flute opening at the first flow face and a flute closure towards the second flow face, where a first flute of the first plurality of flutes defines a first flute distance and a second flute of the first plurality of flutes defines a second flute distance, and wherein the first flute distance and the second flute distance differ by greater than 2 mm.

Embodiment 2. The filter assembly of one of embodiments 1 and 3-17, wherein the first sheet of filter media and the second sheet of filter media are discontinuous.

Embodiment 3. The filter assembly of one of embodiments 1-2 and 4-17, wherein the first sheet of filter media and the second sheet of filter media are continuous and separated by a fold.

Embodiment 4. The filter assembly of one of embodiments 1-3 and 5-17, wherein the flute closure is adjacent to the second flow face.

Embodiment 5. The filter assembly of one of embodiments 1-4 and 6-17, further comprising a third sheet of filter media, wherein the third sheet of filter media and the second sheet of filter media mutually define a second plurality of flutes, the first flow face, and the second flow face, wherein each of the second plurality of flutes extends from the first flow face to the second flow face and each of the second plurality of flutes defines a flute opening at the second flow face and a flute closure towards the first flow face.

Embodiment 6. The filter assembly of one of embodiments 1-5 and 7-17, wherein the second plurality of flutes comprises a third flute defining a third flute distance from the first flow face to the second flow face, wherein the third flute distance differs from the first flute distance and the second flute distance by greater than 2 mm.

Embodiment 7. The filter assembly of one of embodiments 1-6 and 8-17, wherein the first plurality of flutes comprises a third flute defining a third flute distance, wherein the third flute distance differs from the first flute distance and the second flute distance by greater than 2 mm.

Embodiment 8. The filter assembly of one of embodiments 1-7 and 9-17, wherein the first flute distance differs from the second flute distance by at least 5 mm.

Embodiment 9. The filter assembly of one of embodiments 1-8 and 10-17, wherein the first flute distance differs from the second flute distance by 3 mm to 20 mm.

Embodiment 10. The filter assembly of one of embodiments 1-9 and 11-17, wherein the first flute distance differs from the second flute distance by at least 8 mm.

Embodiment 11. The filter assembly of one of embodiments 1-10 and 12-17, wherein the first flute distance differs from the second flute distance by at least 15 mm.

Embodiment 12. The filter assembly of one of embodiments 1-11 and 13-17, wherein the first flow face and the second flow face are non-parallel.

Embodiment 13. The filter assembly of one of embodiments 1-12 and 14-17, wherein at least one of the first flow face and the second flow face is non-planar.

Embodiment 14. The filter assembly of one of embodiments 1-13 and 15-17, wherein at least one of the first flow face and the second flow face is recessed.

Embodiment 15. The filter assembly of one of embodiments 1-14 and 16-17, wherein at least one of the first flow face and the second flow face is planar.

Embodiment 16. The filter assembly of one of embodiments 1-15 and 17-17, wherein the first flow face and the second flow face are both non-planar.

Embodiment 17. The filter assembly of one of embodiments 1-16 and 18, wherein the first sheet is a fluted sheet of filter media and the second sheet is a facing sheet of filter media.

Embodiment 18. The filter assembly of one of embodiments 1-17, wherein both the first sheet and the second sheet are fluted sheets of filter media.

Embodiment 19. A filter assembly comprising:

filter media defining a coiled configuration about a z-axis, wherein:

the filter media defines a first flow face, a second flow face and a plurality of flutes extending from the first flow face to the second flow face, and

the plurality of flutes comprises a first flute defining a first flute distance between the first flow face and the second flow face and a second flute defining a second flute distance between the first flow face and the second flow face, wherein the first flute distance differs from the second flute distance by greater than 2 mm.

Embodiment 20. The filter assembly of one of embodiments 19 and 21-32, wherein the second flow face is non-parallel to the first flow face.

Embodiment 21. The filter assembly of one of embodiments 19-20 and 22-32, wherein the first flow face is non-planar and the second flow face is planar.

Embodiment 22. The filter assembly of one of embodiments 19-21 and 23-32, wherein the first flow face in non-planar and the second flow face is non-planar.

Embodiment 23. The filter assembly of one of embodiments 19-22 and 24-32, wherein one of the first flow face and the second flow face is recessed.

Embodiment 24. The filter assembly of one of embodiments 19-23 and 25-32, comprising a first sheet of filter media and a second sheet of filter media adjacent to the first sheet of filter media, wherein the first sheet and the second sheet defines a coiled configuration about the z-axis and the first sheet and the second sheet mutually define the plurality of flutes.

Embodiment 25. The filter assembly of one of embodiments 19-24 and 26-32, wherein the first sheet and the second sheet are discontinuous.

Embodiment 26. The filter assembly of one of embodiments 19-25 and 27-32, wherein the first sheet and the second sheet are continuous and separated by a fold that defines the second flow face.

Embodiment 27. The filter assembly of one of embodiments 19-26 and 28-32, wherein the first sheet of filter media has a first width defined by the first flow face and the second flow face and the second sheet of filter media has a second width defined by the first flow face and the second flow face and the first width differs from the second width by greater than 2 mm.

Embodiment 28. The filter assembly of one of embodiments 19-27 and 29-32, wherein the first sheet of filter media is a fluted sheet and the second sheet of filter media is a facing sheet.

Embodiment 29. The filter assembly of one of embodiments 19-28 and 32-32, wherein the first flute distance differs from the second flute distance by at least 5 mm.

Embodiment 30. The filter assembly of one of embodiments 19-29 and 31-32, wherein the first flute distance differs from the second flute distance by 3 mm to 20 mm.

Embodiment 31. The filter assembly of one of embodiments 19-30 and 32, wherein the first flute distance differs from the second flute distance by at least 8 mm.

Embodiment 32. The filter assembly of one of embodiments 19-31, wherein the first flute distance differs from the second flute distance by at least 15 mm.

Embodiment 33. A panel filter assembly comprising:

a plurality of sheets of filter media in a stacked configuration mutually defining a first flow face, a second flow face, and a plurality of flutes extending from the first flow face to the second flow face, wherein:

the plurality of sheets of filter media defines a regularly alternating pattern of first flute layers and second flute layers, where each of the first layers defines a first layer distance between the first flow face and the second flow face and each of the second layers defines a second layer distance between the first flow face and the second flow face, and

the first layer distance and the second layer distance differ by greater than 2 mm.

Embodiment 34. The panel filter assembly of one of embodiments 33 and 35-48, wherein each of the plurality of flutes defines a flute opening and a flute closure.

Embodiment 35. The panel filter assembly of one of embodiments 33-34 and 36-48, wherein each of the first layers and second layers is defined by a fluted sheet and an adjacent facing sheet.

Embodiment 36. The panel filter assembly of one of embodiments 33-35 and 37-48, wherein each fluted sheet and facing sheet in each flute layer defines substantially equal distances between the first flow face and the second flow face.

Embodiment 37. The panel filter assembly of one of embodiments 33-36 and 38-48, wherein each fluted sheet and facing sheet in at least one flute layer defines distances between the first flow face and the second flow face that differ by greater than 2 mm.

Embodiment 38. The panel filter assembly of one of embodiments 33-37 and 39-48, wherein each of the first layers and second layers is defined by two adjacent fluted sheets of filter media.

Embodiment 39. The panel filter assembly of one of embodiments 33-38 and 40-48, wherein the plurality of sheets of filter media are discontinuous.

Embodiment 40. The panel filter assembly of one of embodiments 33-39 and 41-48, wherein the plurality of sheets of filter media are continuous and separated by a first set of folds forming the first flow face and a second set of folds forming the second flow face.

Embodiment 41. The panel filter assembly of one of embodiments 33-40 and 42-48, wherein the plurality of sheets of filter media further defines a regularly alternating pattern of third flute layers, where each third flute layer has a third layer distance between the first flow face and the second flow face, wherein the third layer distance differs from the first layer distance and the second layer distance by greater than 2 mm.

Embodiment 42. The panel filter assembly of one of embodiments 33-41 and 43-48, wherein the plurality of sheets of filter media further defines a regularly alternating pattern of fourth flute layers, where each fourth flute layer has a fourth layer distance between the first flow face and the second flow face, wherein the fourth layer distance differs from the first layer distance, the second layer distance, and the third layer distance by greater than 2 mm.

Embodiment 43. The panel filter assembly of one of embodiments 33-42 and 44-48, wherein the second flow face is planar.

Embodiment 44. The panel filter assembly of one of embodiments 33-43 and 45-48, wherein the first flow face and the second flow face are non-planar.

Embodiment 45. The panel filter assembly of one of embodiments 33-44 and 46-48, wherein the first layer distance differs from the second layer distance by at least 5 mm.

Embodiment 46. The panel filter assembly of one of embodiments 33-45 and 47-48, wherein the first layer distance differs from the second layer distance by 3 mm to 20 mm.

Embodiment 47. The panel filter assembly of one of embodiments 33-46 and 48, wherein the first layer distance differs from the second layer distance by at least 8 mm.

Embodiment 48. The panel filter assembly of one of embodiments 33-47, wherein the first layer distance differs from the second layer distance by at least 14 mm.

Embodiment 49. A filter assembly comprising:

a first sheet of filter media and a second sheet of filter media mutually defining a first plurality of flutes, a first flow face, and a second flow face, wherein

each of the first plurality of flutes extends from the first flow face to the second flow face,

each of the first plurality of flutes defines a flute opening at the first flow face and a flute closure towards the second flow face, and

at least one of the first flow face and the second flow face is recessed.

Embodiment 50. The filter assembly of one of embodiments 49 and 51-62, wherein the first sheet is a fluted sheet of filter media and the second sheet is a facing sheet of filter media.

Embodiment 51. The filter assembly of one of embodiments 49-50 and 52-62, wherein both the first sheet and the second sheet are fluted sheets of filter media.

Embodiment 52. The filter assembly of one of embodiments 49-51 and 53-62, wherein the flute closure is adjacent to the second flow face.

Embodiment 53. The filter assembly of one of embodiments 49-52 and 54-62, further comprising a third sheet of filter media, wherein the third sheet of filter media and the second sheet of filter media mutually define a second plurality of flutes, the first flow face, and the second flow face, wherein each of the second plurality of flutes extends from the first flow face to the second flow face and each of the second plurality of flutes defines a flute opening at the second flow face and a flute closure towards the first flow face.

Embodiment 54. The filter assembly of one of embodiments 49-53 and 55-62, wherein the first plurality of flutes has a first flute defining a first flute distance between the first flow face and the second flow face and a second flute defining a second flute distance between the first flow face and the second flow face, and the second plurality of flutes has a third flute defining a third flute distance between the first flow face and the second flow face, and each of the first flute distance, second flute distance, and third flute distance differ by greater than 2 mm.

Embodiment 55. The filter assembly of one of embodiments 49-54 and 56-62, wherein the filter assembly is a panel filter.

Embodiment 56. The filter assembly of one of embodiments 49-55 and 57-62, wherein the first sheet of filter media and the second sheet of filter media define a coiled configuration about a z-axis.

Embodiment 57. The filter assembly of one of embodiments 49-56 and 58-62, wherein the first sheet of filter media and the second sheet of filter media are continuous and separated by a fold that defines the second flow face.

Embodiment 58. The filter assembly of one of embodiments 49-57 and 59-62, wherein a first flute of the first plurality of flutes defines a first flute distance between the first flow face and the second flow face and a second flute of the first plurality of flutes defines a second flute distance between the first flow face and the second flow face, and the first flute distance differs from the second flute distance by greater than 2 mm.

Embodiment 59. The filter assembly of one of embodiments 49-58 and 60-62, wherein the first flow face and the second flow face are both non-planar.

Embodiment 60. The filter assembly of one of embodiments 49-59 and 61-62, wherein the first sheet and the second sheet are discontinuous.

Embodiment 61. The filter assembly of one of embodiments 49-60 and 62, wherein the first flow face is opposite the second flow face relative to the filter assembly.

Embodiment 62. The filter assembly of one of embodiments 49-61, wherein the plurality of flutes are parallel.

Embodiment 63. A panel filter assembly comprising:

a plurality of stacked sheets of filter media each having a width extending in a direction parallel to an x-axis and a length extending in a direction parallel to a z-axis, wherein:

the plurality of sheets of filter media are stacked in a direction parallel to a y-axis,

the plurality of sheets of filter media define a plurality of flutes, a first flow face, and a second flow face,

each of the plurality of flutes defines a flute opening at the first flow face and a flute closure towards the second flow face,

a first flute of the plurality of flutes defines a first flute distance between the first flow face and the second flow face, a second flute of the plurality of flutes defines a second flute distance between the first flow face and the second flow face, and a third flute of the plurality of flutes defines a third flute distance between the first flow face and the second flow face, the second flute is adjacent the first flute in an x-axis direction, and the third flute is positioned relative to the first flute in a y-axis direction, and

the first flute distance differs from the second flute distance by greater than 2 mm and the first flute distance differs from the third flute distance by greater than 2 mm.

Embodiment 64. The panel filter assembly of one of embodiments 63 and 65-76, wherein the plurality of stacked sheets of filter media are discontinuous.

Embodiment 65. The panel filter assembly of one of embodiments 63-64 and 66-76, wherein the plurality of stacked sheets of filter media are continuous and separated by folds.

Embodiment 66. The panel filter assembly of one of embodiments 63-65 and 67-76, wherein first flute distance, the second flute distance, and the third flute distance differ by greater than 2 mm.

Embodiment 67. The panel filter assembly of one of embodiments 63-66 and 68-76, wherein at least one of the first flow face and the second flow face is non-planar.

Embodiment 68. The panel filter assembly of one of embodiments 63-67 and 69-76, wherein at least one of the first flow face and the second flow face is recessed.

Embodiment 69. The panel filter assembly of one of embodiments 63-68 and 70-76, wherein the first flow face and the second flow face are both non-planar.

Embodiment 70. The panel filter assembly of one of embodiments 63-69 and 71-76, wherein the first flow face and the second flow face are non-parallel.

Embodiment 71. The panel filter assembly of one of embodiments 63-70 and 72-76, wherein the first flute distance differs from the second flute distance and the third flute distance by at least 5 mm.

Embodiment 72. The panel filter assembly of one of embodiments 63-71 and 73-76, wherein the first flute distance differs from the second flute distance and the third flute distance by 3 mm to 20 mm.

Embodiment 73. The panel filter assembly of one of embodiments 63-72 and 74-76, wherein the first flute distance differs from the second flute distance and the third flute distance by at least 8 mm.

Embodiment 74. The panel filter assembly of one of embodiments 63-73 and 75-76, wherein the first flute distance differs from the second flute distance and the third flute distance by at least 15 mm.

Embodiment 75. The panel filter assembly of one of embodiments 63-74 and 76, wherein the plurality of stacked sheets of filter media comprise alternating fluted sheets of filter media and facing sheets of filter media.

Embodiment 76. The panel filter assembly of one of embodiments 63-75, wherein each of the plurality of stacked sheets of filter media are fluted sheets of filter media.

Embodiment 77. A filter assembly comprising:

filter media defining a plurality of flutes, a first edge defining a first flow face, and a second flow face opposite the first flow face relative to the filter assembly, wherein:

each of the plurality of flutes defines a flute opening at the first flow face and a flute closure towards the second flow face, and

the plurality of flutes comprises at least one flute defining a flute opening that is non-planar.

Embodiment 78. The filter assembly of one of embodiments 77 and 79-90, wherein the filter media comprises a plurality of sheets of filter media in a stacked configuration.

Embodiment 79. The filter assembly of one of embodiments 77-78 and 80-90, wherein the plurality of sheets of filter media comprise alternating fluted sheets of filter media and facing sheets of filter media.

Embodiment 80. The filter assembly of one of embodiments 77-79 and 81-90, wherein the plurality of sheets of filter media are fluted sheets of filter media.

Embodiment 81. The filter assembly of one of embodiments 77-80 and 82-90, wherein the filter media comprises a first sheet of filter media and a second sheet of filter media in a coiled configuration about a z-axis.

Embodiment 82. The filter assembly of one of embodiments 77-81 and 83-90, wherein the first sheet of filter media is a fluted sheet and the second sheet of filter media is a facing sheet.

Embodiment 83. The filter assembly of one of embodiments 77-82 and 84-90, wherein the filter assembly is a panel filter.

Embodiment 84. The filter assembly of one of embodiments 77-83 and 85-90, wherein the first flute of the plurality of flutes defines a first flute distance between the first flow face and the second flow face and a second flute of the plurality of flutes defines a second flute distance between the first flow face and the second flow face, and the first flute distance differs from the second flute distance by greater than 2 mm.

Embodiment 85. The filter assembly of one of embodiments 77-84 and 86-90, wherein the first flute distance differs from the second flute distance by at least 5 mm.

Embodiment 86. The filter assembly of one of embodiments 77-85 and 87-90, wherein the first flute distance differs from the second flute distance by 3 mm to 20 mm.

Embodiment 87. The filter assembly of one of embodiments 77-86 and 88-90, wherein the first flute distance differs from the second flute distance by at least 8 mm.

Embodiment 88. The filter assembly of one of embodiments 77-87 and 89-90, wherein the first flute distance differs from the second flute distance by at least 15 mm.

Embodiment 89. The filter assembly of one of embodiments 77-88 and 90, wherein the first flow face and the second flow face are both non-planar.

Embodiment 90. The filter assembly of one of embodiments 77-89, wherein the flute closure is adjacent the second flow face.

Embodiment 91. A filter assembly comprising:

a first sheet of filter media and a second sheet of filter media mutually defining a first plurality of flutes, a first flow face, and a second flow face, wherein

each of the first plurality of flutes extends from the first flow face to the second flow face,

each of the first plurality of flutes defines a flute opening at the first flow face and a flute closure towards the second flow face,

the first flow face and the second flow face are planar, and

the first flow face is non-parallel to the second flow face.

Embodiment 92. The filter assembly of one of embodiments 91 and 93-103, wherein the first sheet is a fluted sheet of filter media and the second sheet is a facing sheet of filter media.

Embodiment 93. The filter assembly of one of embodiments 91-92 and 94-103, wherein both the first sheet and the second sheet are fluted sheets of filter media.

Embodiment 94. The filter assembly of one of embodiments 91-93 and 95-103, wherein the flute closure is adjacent to the second flow face.

Embodiment 95. The filter assembly of one of embodiments 91-94 and 96-103, further comprising a third sheet of filter media, wherein the third sheet of filter media and the second sheet of filter media mutually define a second plurality of flutes, the first flow face, and the second flow face, wherein each of the second plurality of flutes extends from the first flow face to the second flow face and each of the second plurality of flutes defines a flute opening at the second flow face and a flute closure towards the first flow face.

Embodiment 96. The filter assembly of one of embodiments 91-95 and 97-103, wherein the first plurality of flutes has a first flute defining a first flute distance between the first flow face and the second flow face and a second flute defining a second flute distance between the first flow face and the second flow face, and the second plurality of flutes has a third flute defining a third flute distance between the first flow face and the second flow face, and each of the first flute distance, second flute distance, and third flute distance differ by greater than 2 mm.

Embodiment 97. The filter assembly of one of embodiments 91-96 and 98-103, wherein the filter assembly is a panel filter.

Embodiment 98. The filter assembly of one of embodiments 91-97 and 99-103, wherein the first sheet of filter media and the second sheet of filter media define a coiled configuration about a z-axis.

Embodiment 99. The filter assembly of one of embodiments 91-98 and 100-103, wherein a first flute of the first plurality of flutes defines a first flute distance between the first flow face and the second flow face and a second flute of the first plurality of flutes defines a second flute distance between the first flow face and the second flow face, and the first flute distance differs from the second flute distance by greater than 2 mm.

Embodiment 100. The filter assembly of one of embodiments 91-99 and 101-103, wherein the first sheet and the second sheet are discontinuous.

Embodiment 101. The filter assembly of one of embodiments 91-100 and 102-103, wherein the first sheet and the second sheet are continuous and separated by a fold.

Embodiment 102. The filter assembly of one of embodiments 91-101 and 103, wherein the first flow face is opposite the second flow face relative to the filter assembly.

Embodiment 103. The filter assembly of one of embodiments 91-102, wherein the first plurality of flutes are parallel.

It should also be noted that, as used in this specification and the appended claims, the phrase “configured” describes a system, apparatus, or other structure that is constructed to perform a particular task or adopt a particular configuration. The word “configured” can be used interchangeably with similar words such as “arranged”, “constructed”, “manufactured”, and the like.

All publications and patent applications in this specification are indicative of the level of ordinary skill in the art to which this technology pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated by reference. In the event that any inconsistency exists between the disclosure of the present application and the disclosure(s) of any document incorporated herein by reference, the disclosure of the present application shall govern.

This application is intended to cover adaptations or variations of the present subject matter. It is to be understood that the above description is intended to be illustrative, and not restrictive, and the claims are not limited to the illustrative embodiments as set forth herein. 

What is claimed is:
 1. A two-stage separator system comprising: a housing extending between a first end and a second end, the housing defining a housing inlet, a separator outlet towards the second end, and a filtration outlet on the first end; and a filter assembly having a first sheet of filter media coupled to a second sheet of filter media mutually defining a plurality of flutes extending in an axial direction, the filter assembly defining an inlet flow face and an outlet flow face, wherein the filter assembly is disposed in the housing and coupled to the housing about the filtration outlet such that the outlet flow face is in fluid communication with the filtration outlet, and wherein the inlet flow face has an axial flow face length.
 2. The system of any one of claims 1 and 3-17, wherein a radial distance is defined between the inlet flow face and the housing, wherein the radial distance increases for at least a portion of the axial flow face length from the first end towards the second end.
 3. The system of any one of claims 1-2 and 4-17, wherein the filter assembly has an outer radial barrier surface extending axially from the filtration outlet beyond the housing inlet.
 4. The system of any one of claims 1-3 and 5-17, wherein the filter assembly has an outer radial barrier surface having an axial length from the outlet flow face towards the inlet flow face that is greater than or equal to an axial distance from the filtration outlet to a distal end of the housing inlet.
 5. The system of any one of claims 1-4 and 6-17, wherein the housing inlet defines an airflow pathway that is tangential to an outer radial barrier surface of the filter assembly.
 6. The system of any one of claims 1-5 and 7-17, wherein at least a portion of the outer radial barrier surface is defined by the first sheet of filter media.
 7. The system of any one of claims 1-6 and 8-17, wherein the inlet flow face defines a taper for at least a portion of the axial flow face length from the first end towards the second end.
 8. The system of any one of claims 1-7 and 9-17, wherein the taper increases for at least a portion of the axial flow face length from the first end towards the second end.
 9. The system of any one of claims 1-8 and 10-17, wherein the taper continuously changes along the axial flow face length from the first end towards the second end.
 10. The system of any one of claims 1-9 and 11-17, wherein the taper continuously increases along the axial flow face length from the first end towards the second end.
 11. The system of any one of claims 1-10 and 12-17, wherein the first sheet of filter media is a facing sheet and the second sheet of filter media is a fluted sheet.
 12. The system of any one of claims 1-11 and 13-17, wherein the first sheet of filter media and the second sheet of filter media define a coiled configuration about a z-axis extending in the axial direction.
 13. The system of any one of claims 1-12 and 14-17, further comprising: a rod extending centrally through the filter assembly, the rod having a proximal end positioned towards the outlet flow face and a distal end positioned towards the inlet flow face; and a rod receptacle defined by the second end of the housing, wherein the rod receptacle is configured to receive the distal end of the rod.
 14. The system of any one of claims 1-13 and 15-17, wherein the distal end of the rod defines a handle.
 15. The system of any one of claims 1-14 and 16-17, wherein the filter assembly has a circular cross-section.
 16. The system of any one of claims 1-15, and 17 wherein the filter assembly comprises: a plurality of first sheets of filter media and a plurality of second sheets of filter media in an alternating, stacked configuration; and a radial sleeve disposed about the stacked first sheets of filter media and second sheets of filter media.
 17. The system of any one of claims 1-16, wherein the housing inlet is defined towards the first end of the housing. 